phase: 94_ls_tree_drilldown

All green. Verification complete.

**Phase 94 — `ls` drill-down tree: final verification pass (all 5 tasks were already complete; verified, nothing to fix)**

- Verified `ls` 3-level tree (`app/rag/agent.py`): `ls()` sources + summaries, `ls(source)`/`ls(source/folder)` drill-down, 50-line file cap + grep-pointer note, NOT-A-FOLDER teaching refusal
- Verified `folder_summaries` (migration 0017, model, `app/rag/folder_summaries.py` generator: `FOLDER_SUMMARY_MODE` marker, fail-soft per folder, ≥2-doc scope + prune) wired change-gated in both sync paths
- Verified 10-turn fixture battery verdict recorded in `TOOL_CALLING_TESTING.md` §9 (2026-09-11): turbo PASS 19/19 contract, 98.7 s (−12.5…−13.2 % vs baseline); lite PASS 18/18, 43.6 s (+7.7 %) — accuracy at/above baseline, gate met
- `uv run pytest --cov=app --cov-report=term-missing` → 1939 passed, 0 failed; TOTAL coverage **99 %** (folder_summaries.py 100 %)
- `uv run ruff check .` → clean; `uv run pyright` → 0 errors, 0 warnings
- E2E in isolation: `test_ls_tree_drilldown.py` 3 passed; `test_agent_document_tools` 4, `test_agent_unlimited_tools` 4, `test_harness_aligned_tools` 3, `test_search_tool` 3, `test_grep_regex_teaching` 2, `test_response_to_docs` 4 — all passed (read/grep contracts untouched)
- Dedicated folder-summary tests (fail-soft, prune, both sync paths, migration): 46 passed
- Completion criteria: all 6 met; working tree holds only phase-94 changes (commit left to harness per protocol)

**Next pending phase:** `95_read_truncation_cap`

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__00_phase.a1.md

@@ -0,0 +1,14 @@
+All green. Verification complete.
+
+**Phase 94 — `ls` drill-down tree: final verification pass (all 5 tasks were already complete; verified, nothing to fix)**
+
+- Verified `ls` 3-level tree (`app/rag/agent.py`): `ls()` sources + summaries, `ls(source)`/`ls(source/folder)` drill-down, 50-line file cap + grep-pointer note, NOT-A-FOLDER teaching refusal
+- Verified `folder_summaries` (migration 0017, model, `app/rag/folder_summaries.py` generator: `FOLDER_SUMMARY_MODE` marker, fail-soft per folder, ≥2-doc scope + prune) wired change-gated in both sync paths
+- Verified 10-turn fixture battery verdict recorded in `TOOL_CALLING_TESTING.md` §9 (2026-09-11): turbo PASS 19/19 contract, 98.7 s (−12.5…−13.2 % vs baseline); lite PASS 18/18, 43.6 s (+7.7 %) — accuracy at/above baseline, gate met
+- `uv run pytest --cov=app --cov-report=term-missing` → 1939 passed, 0 failed; TOTAL coverage **99 %** (folder_summaries.py 100 %)
+- `uv run ruff check .` → clean; `uv run pyright` → 0 errors, 0 warnings
+- E2E in isolation: `test_ls_tree_drilldown.py` 3 passed; `test_agent_document_tools` 4, `test_agent_unlimited_tools` 4, `test_harness_aligned_tools` 3, `test_search_tool` 3, `test_grep_regex_teaching` 2, `test_response_to_docs` 4 — all passed (read/grep contracts untouched)
+- Dedicated folder-summary tests (fail-soft, prune, both sync paths, migration): 46 passed
+- Completion criteria: all 6 met; working tree holds only phase-94 changes (commit left to harness per protocol)
+
+**Next pending phase:** `95_read_truncation_cap`

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__00_phase.a1.validate

@@ -0,0 +1,94 @@
+........................................................................ [  3%]
+........................................................................ [  7%]
+........................................................................ [ 11%]
+........................................................................ [ 14%]
+........................................................................ [ 18%]
+........................................................................ [ 22%]
+........................................................................ [ 25%]
+........................................................................ [ 29%]
+........................................................................ [ 33%]
+........................................................................ [ 37%]
+........................................................................ [ 40%]
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+........................................................................ [ 63%]
+........................................................................ [ 66%]
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+........................................................................ [ 77%]
+........................................................................ [ 81%]
+........................................................................ [ 85%]
+........................................................................ [ 89%]
+........................................................................ [ 92%]
+........................................................................ [ 96%]
+...................................................................      [100%]
+=============================== warnings summary ===============================
+.venv/lib/python3.13/site-packages/fastapi/testclient.py:1
+  /var/home/ducoterra/Projects/Personal/brain_of_reese/.venv/lib/python3.13/site-packages/fastapi/testclient.py:1: StarletteDeprecationWarning: Using `httpx` with `starlette.testclient` is deprecated; install `httpx2` instead.
+    from starlette.testclient import TestClient as TestClient  # noqa
+
+-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
+================================ tests coverage ================================
+_______________ coverage: platform linux, python 3.13.13-final-0 _______________
+
+Name                           Stmts   Miss  Cover
+--------------------------------------------------
+app/__init__.py                    1      0   100%
+app/api/__init__.py                0      0   100%
+app/api/auth.py                   52      0   100%
+app/api/chat.py                  178      0   100%
+app/api/chats.py                 110      0   100%
+app/api/config.py                 13      0   100%
+app/api/doc_drafts.py             94      0   100%
+app/api/docs.py                   50      0   100%
+app/api/git_sources.py           229      0   100%
+app/api/health.py                 10      0   100%
+app/api/steering.py               42      0   100%
+app/api/suggestions.py            29      0   100%
+app/api/sync.py                  110      0   100%
+app/api/tokens.py                 28      0   100%
+app/api/ui_settings.py            55      0   100%
+app/config.py                    133      0   100%
+app/core/__init__.py               0      0   100%
+app/core/auth.py                  45      0   100%
+app/core/caching.py              124      0   100%
+app/core/debugging.py             29      2    93%
+app/core/docs_push.py             39      0   100%
+app/core/errors.py                 5      0   100%
+app/core/logging.py               13      0   100%
+app/core/rate_limit.py            44      0   100%
+app/core/security_headers.py      20      0   100%
+app/core/theming.py               38      0   100%
+app/core/tokens.py                33      0   100%
+app/db.py                         21      0   100%
+app/main.py                       66      0   100%
+app/models.py                    124      0   100%
+app/rag/__init__.py                0      0   100%
+app/rag/agent.py                 306      1    99%
+app/rag/archive_upload.py        128      0   100%
+app/rag/chunker.py               206      4    98%
+app/rag/folder_summaries.py      110      0   100%
+app/rag/git_sources.py            14      0   100%
+app/rag/importer.py              190      3    98%
+app/rag/llm.py                   217      0   100%
+app/rag/overview.py               71      0   100%
+app/rag/prompts.py                88      0   100%
+app/rag/retriever.py             150      3    98%
+app/rag/scaffolding.py            55      0   100%
+app/rag/source_removal.py         41      0   100%
+app/rag/sources_meta.py           16      0   100%
+app/rag/suggestions.py            27      0   100%
+app/rag/summarizer.py             24      0   100%
+app/schemas.py                   269      0   100%
+--------------------------------------------------
+TOTAL                           3647     13    99%
+coverage gate: app/ 99% (>90%) OK
+All checks passed!
+0 errors, 0 warnings, 0 informations
+WARNING: there is a new pyright version available (v1.1.411 -> v1.1.414).
+Please install the new version or set PYRIGHT_PYTHON_FORCE_VERSION to `latest`
+
+validation OK

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__01_folder_summary_model.a1.md

@@ -0,0 +1,17 @@
+Task 01 is complete and fully verified.
+
+**Implemented** (phase 94, task 01 — folder summary storage + generator)
+- `alembic/versions/0017_folder_summaries.py`: `folder_summaries` table, PK `(source, folder_path)` mirroring `documents` String(120)/String(1000), TEXT `summary` NOT NULL, TIMESTAMPTZ `updated_at` (now() default); tested downgrade
+- `app/models.py`: `FolderSummary` model (`folder_path = ""` = source root; ≥2-doc policy documented)
+- `app/rag/folder_summaries.py`: `FOLDER_SUMMARY_MODE` marker + 1–3-sentence locked instruction, `folder_of`, `group_by_folder` (recursive subtree = exactly the `ls` count rule — I fixed a gap: the `path == folder` arm now lands a file-sharing-a-directory-name in its folder's group), capped prompt builder (8 000 chars, `BOR_FOLDER_SUMMARY_INPUT_MAX_CHARS` + `TRUNCATION_MARKER`), `summarize_folder` (empty→`LLMError`), `generate_folder_summaries` (skip no-op, per-folder fail-soft, ≥2 rule, stale prune, flush-only caller-commits, stats dict + log line)
+- `tests/e2e/mock_llm.py`: canned `Fixture folder summary for <folder>.` branch, checked **before** the `SUMMARY_MODE` branch (marker-substring shadowing — real bug, pinned)
+- Tests: 31 unit + 4 migration integration; also repaired dev DB (found at 0006 → upgraded to 0017 head)
+
+**Results**
+- `uv run pytest --cov=app --cov-report=term-missing` → **1903 passed, TOTAL 99%** (`folder_summaries.py` 100%, `models.py` 100%)
+- `uv run ruff check . && uv run pyright` → clean (0 errors)
+- E2E in isolation, all PASS: `test_harness_aligned_tools`, `test_agent_document_tools`, `test_agent_unlimited_tools`, `test_search_tool`, `test_grep_regex_teaching`, `test_response_to_docs`, `test_kb_overview`, `test_document_summaries`
+
+**Notable** — a previous (a1) attempt's work was in the tree; I verified rather than trusted it, fixed the `group_by_folder` concept gap, and added the mock-branch + edge-case pins.
+
+**Next pending task** — `.agents/phases/todo/94_ls_tree_drilldown/02_sync_wiring.md`

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__01_folder_summary_model.a1.validate

@@ -0,0 +1,94 @@
+........................................................................ [  3%]
+........................................................................ [  7%]
+........................................................................ [ 11%]
+........................................................................ [ 15%]
+........................................................................ [ 18%]
+........................................................................ [ 22%]
+........................................................................ [ 26%]
+........................................................................ [ 30%]
+........................................................................ [ 34%]
+........................................................................ [ 37%]
+........................................................................ [ 41%]
+........................................................................ [ 45%]
+........................................................................ [ 49%]
+........................................................................ [ 52%]
+........................................................................ [ 56%]
+........................................................................ [ 60%]
+........................................................................ [ 64%]
+........................................................................ [ 68%]
+........................................................................ [ 71%]
+........................................................................ [ 75%]
+........................................................................ [ 79%]
+........................................................................ [ 83%]
+........................................................................ [ 87%]
+........................................................................ [ 90%]
+........................................................................ [ 94%]
+........................................................................ [ 98%]
+...............................                                          [100%]
+=============================== warnings summary ===============================
+.venv/lib/python3.13/site-packages/fastapi/testclient.py:1
+  /var/home/ducoterra/Projects/Personal/brain_of_reese/.venv/lib/python3.13/site-packages/fastapi/testclient.py:1: StarletteDeprecationWarning: Using `httpx` with `starlette.testclient` is deprecated; install `httpx2` instead.
+    from starlette.testclient import TestClient as TestClient  # noqa
+
+-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
+================================ tests coverage ================================
+_______________ coverage: platform linux, python 3.13.13-final-0 _______________
+
+Name                           Stmts   Miss  Cover
+--------------------------------------------------
+app/__init__.py                    1      0   100%
+app/api/__init__.py                0      0   100%
+app/api/auth.py                   52      0   100%
+app/api/chat.py                  178      0   100%
+app/api/chats.py                 110      0   100%
+app/api/config.py                 13      0   100%
+app/api/doc_drafts.py             94      0   100%
+app/api/docs.py                   50      0   100%
+app/api/git_sources.py           229      0   100%
+app/api/health.py                 10      0   100%
+app/api/steering.py               42      0   100%
+app/api/suggestions.py            29      0   100%
+app/api/sync.py                  101      0   100%
+app/api/tokens.py                 28      0   100%
+app/api/ui_settings.py            55      0   100%
+app/config.py                    133      0   100%
+app/core/__init__.py               0      0   100%
+app/core/auth.py                  45      0   100%
+app/core/caching.py              124      0   100%
+app/core/debugging.py             29      2    93%
+app/core/docs_push.py             39      0   100%
+app/core/errors.py                 5      0   100%
+app/core/logging.py               13      0   100%
+app/core/rate_limit.py            44      0   100%
+app/core/security_headers.py      20      0   100%
+app/core/theming.py               38      0   100%
+app/core/tokens.py                33      0   100%
+app/db.py                         21      0   100%
+app/main.py                       66      0   100%
+app/models.py                    124      0   100%
+app/rag/__init__.py                0      0   100%
+app/rag/agent.py                 222      0   100%
+app/rag/archive_upload.py        128      0   100%
+app/rag/chunker.py               206      4    98%
+app/rag/folder_summaries.py      108      0   100%
+app/rag/git_sources.py            14      0   100%
+app/rag/importer.py              190      3    98%
+app/rag/llm.py                   217      0   100%
+app/rag/overview.py               71      0   100%
+app/rag/prompts.py                88      0   100%
+app/rag/retriever.py             150      3    98%
+app/rag/scaffolding.py            55      0   100%
+app/rag/source_removal.py         41      0   100%
+app/rag/sources_meta.py           16      0   100%
+app/rag/suggestions.py            27      0   100%
+app/rag/summarizer.py             24      0   100%
+app/schemas.py                   269      0   100%
+--------------------------------------------------
+TOTAL                           3552     12    99%
+coverage gate: app/ 99% (>90%) OK
+All checks passed!
+0 errors, 0 warnings, 0 informations
+WARNING: there is a new pyright version available (v1.1.411 -> v1.1.414).
+Please install the new version or set PYRIGHT_PYTHON_FORCE_VERSION to `latest`
+
+validation OK

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__02_sync_wiring.a1.md

@@ -0,0 +1 @@
+(no final assistant message — see the .err log)

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__02_sync_wiring.a1.validate

@@ -0,0 +1,94 @@
+........................................................................ [  3%]
+........................................................................ [  7%]
+........................................................................ [ 11%]
+........................................................................ [ 15%]
+........................................................................ [ 18%]
+........................................................................ [ 22%]
+........................................................................ [ 26%]
+........................................................................ [ 30%]
+........................................................................ [ 34%]
+........................................................................ [ 37%]
+........................................................................ [ 41%]
+........................................................................ [ 45%]
+........................................................................ [ 49%]
+........................................................................ [ 52%]
+........................................................................ [ 56%]
+........................................................................ [ 60%]
+........................................................................ [ 64%]
+........................................................................ [ 68%]
+........................................................................ [ 71%]
+........................................................................ [ 75%]
+........................................................................ [ 79%]
+........................................................................ [ 83%]
+........................................................................ [ 87%]
+........................................................................ [ 90%]
+........................................................................ [ 94%]
+........................................................................ [ 98%]
+...............................                                          [100%]
+=============================== warnings summary ===============================
+.venv/lib/python3.13/site-packages/fastapi/testclient.py:1
+  /var/home/ducoterra/Projects/Personal/brain_of_reese/.venv/lib/python3.13/site-packages/fastapi/testclient.py:1: StarletteDeprecationWarning: Using `httpx` with `starlette.testclient` is deprecated; install `httpx2` instead.
+    from starlette.testclient import TestClient as TestClient  # noqa
+
+-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
+================================ tests coverage ================================
+_______________ coverage: platform linux, python 3.13.13-final-0 _______________
+
+Name                           Stmts   Miss  Cover
+--------------------------------------------------
+app/__init__.py                    1      0   100%
+app/api/__init__.py                0      0   100%
+app/api/auth.py                   52      0   100%
+app/api/chat.py                  178      0   100%
+app/api/chats.py                 110      0   100%
+app/api/config.py                 13      0   100%
+app/api/doc_drafts.py             94      0   100%
+app/api/docs.py                   50      0   100%
+app/api/git_sources.py           229      0   100%
+app/api/health.py                 10      0   100%
+app/api/steering.py               42      0   100%
+app/api/suggestions.py            29      0   100%
+app/api/sync.py                  101      0   100%
+app/api/tokens.py                 28      0   100%
+app/api/ui_settings.py            55      0   100%
+app/config.py                    133      0   100%
+app/core/__init__.py               0      0   100%
+app/core/auth.py                  45      0   100%
+app/core/caching.py              124      0   100%
+app/core/debugging.py             29      2    93%
+app/core/docs_push.py             39      0   100%
+app/core/errors.py                 5      0   100%
+app/core/logging.py               13      0   100%
+app/core/rate_limit.py            44      0   100%
+app/core/security_headers.py      20      0   100%
+app/core/theming.py               38      0   100%
+app/core/tokens.py                33      0   100%
+app/db.py                         21      0   100%
+app/main.py                       66      0   100%
+app/models.py                    124      0   100%
+app/rag/__init__.py                0      0   100%
+app/rag/agent.py                 222      0   100%
+app/rag/archive_upload.py        128      0   100%
+app/rag/chunker.py               206      4    98%
+app/rag/folder_summaries.py      108      0   100%
+app/rag/git_sources.py            14      0   100%
+app/rag/importer.py              190      3    98%
+app/rag/llm.py                   217      0   100%
+app/rag/overview.py               71      0   100%
+app/rag/prompts.py                88      0   100%
+app/rag/retriever.py             150      3    98%
+app/rag/scaffolding.py            55      0   100%
+app/rag/source_removal.py         41      0   100%
+app/rag/sources_meta.py           16      0   100%
+app/rag/suggestions.py            27      0   100%
+app/rag/summarizer.py             24      0   100%
+app/schemas.py                   269      0   100%
+--------------------------------------------------
+TOTAL                           3552     12    99%
+coverage gate: app/ 99% (>90%) OK
+All checks passed!
+0 errors, 0 warnings, 0 informations
+WARNING: there is a new pyright version available (v1.1.411 -> v1.1.414).
+Please install the new version or set PYRIGHT_PYTHON_FORCE_VERSION to `latest`
+
+validation OK

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__02_sync_wiring.a2.md

@@ -0,0 +1,14 @@
+All green. Everything for task 02 is implemented, tested, and verified.
+
+**Report — task 02 (sync wiring) completed**
+
+- `scripts/import_docs.py`: `_run()` regenerates `folder_summaries` under the overview's change gate (added+updated>0) or the table-empty first-run trigger; same event loop/LLMClient; generator flushes, the run's own short-lived session commits (phase-53 convention); stats on the summary line as `folder_summaries=<gen>/<fail>/<prune>` or `skipped`; docstrings updated
+- `app/api/sync.py`: step 5 calls the same generator + gate (change or empty table); per-folder fail-soft (a `lite` outage never flips the run and never blocks the bump); stats log-only — `/api/sync/status` detail shape untouched
+- `app/rag/folder_summaries.py`: added `folder_summary_table_empty()` gate probe (LIMIT 1)
+- New `tests/integration/test_sync_folder_summaries.py` (10 tests: changed/unchanged/prune/fail-soft/`--limit`/empty-table on both paths); updated overview/git/sync-API/sync-button suites (pinned line endings + layer stubs per the line-extension rule); +1 unit test for the gate probe
+
+- `uv run pytest --cov=app --cov-report=term-missing` → **1914 passed**, app/ coverage **99%** (>90%)
+- `uv run pytest tests/integration/test_sync_folder_summaries.py -v --no-cov` → 10 passed
+- `uv run ruff check .` → All checks passed; `uv run pyright` → 0 errors
+
+Decisions: line token format `G/F/P|skipped`; `--limit` skip enforced at the caller (early return) with the generator's `skip` flag as tested backstop; API folder gate = change ∨ empty table, overview gate unchanged. Next pending: `03_ls_tree.md`.

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__02_sync_wiring.a2.validate

@@ -0,0 +1,94 @@
+........................................................................ [  3%]
+........................................................................ [  7%]
+........................................................................ [ 11%]
+........................................................................ [ 15%]
+........................................................................ [ 18%]
+........................................................................ [ 22%]
+........................................................................ [ 26%]
+........................................................................ [ 30%]
+........................................................................ [ 33%]
+........................................................................ [ 37%]
+........................................................................ [ 41%]
+........................................................................ [ 45%]
+........................................................................ [ 48%]
+........................................................................ [ 52%]
+........................................................................ [ 56%]
+........................................................................ [ 60%]
+........................................................................ [ 63%]
+........................................................................ [ 67%]
+........................................................................ [ 71%]
+........................................................................ [ 75%]
+........................................................................ [ 78%]
+........................................................................ [ 82%]
+........................................................................ [ 86%]
+........................................................................ [ 90%]
+........................................................................ [ 94%]
+........................................................................ [ 97%]
+..........................................                               [100%]
+=============================== warnings summary ===============================
+.venv/lib/python3.13/site-packages/fastapi/testclient.py:1
+  /var/home/ducoterra/Projects/Personal/brain_of_reese/.venv/lib/python3.13/site-packages/fastapi/testclient.py:1: StarletteDeprecationWarning: Using `httpx` with `starlette.testclient` is deprecated; install `httpx2` instead.
+    from starlette.testclient import TestClient as TestClient  # noqa
+
+-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
+================================ tests coverage ================================
+_______________ coverage: platform linux, python 3.13.13-final-0 _______________
+
+Name                           Stmts   Miss  Cover
+--------------------------------------------------
+app/__init__.py                    1      0   100%
+app/api/__init__.py                0      0   100%
+app/api/auth.py                   52      0   100%
+app/api/chat.py                  178      0   100%
+app/api/chats.py                 110      0   100%
+app/api/config.py                 13      0   100%
+app/api/doc_drafts.py             94      0   100%
+app/api/docs.py                   50      0   100%
+app/api/git_sources.py           229      0   100%
+app/api/health.py                 10      0   100%
+app/api/steering.py               42      0   100%
+app/api/suggestions.py            29      0   100%
+app/api/sync.py                  110      0   100%
+app/api/tokens.py                 28      0   100%
+app/api/ui_settings.py            55      0   100%
+app/config.py                    133      0   100%
+app/core/__init__.py               0      0   100%
+app/core/auth.py                  45      0   100%
+app/core/caching.py              124      0   100%
+app/core/debugging.py             29      2    93%
+app/core/docs_push.py             39      0   100%
+app/core/errors.py                 5      0   100%
+app/core/logging.py               13      0   100%
+app/core/rate_limit.py            44      0   100%
+app/core/security_headers.py      20      0   100%
+app/core/theming.py               38      0   100%
+app/core/tokens.py                33      0   100%
+app/db.py                         21      0   100%
+app/main.py                       66      0   100%
+app/models.py                    124      0   100%
+app/rag/__init__.py                0      0   100%
+app/rag/agent.py                 222      0   100%
+app/rag/archive_upload.py        128      0   100%
+app/rag/chunker.py               206      4    98%
+app/rag/folder_summaries.py      110      0   100%
+app/rag/git_sources.py            14      0   100%
+app/rag/importer.py              190      3    98%
+app/rag/llm.py                   217      0   100%
+app/rag/overview.py               71      0   100%
+app/rag/prompts.py                88      0   100%
+app/rag/retriever.py             150      3    98%
+app/rag/scaffolding.py            55      0   100%
+app/rag/source_removal.py         41      0   100%
+app/rag/sources_meta.py           16      0   100%
+app/rag/suggestions.py            27      0   100%
+app/rag/summarizer.py             24      0   100%
+app/schemas.py                   269      0   100%
+--------------------------------------------------
+TOTAL                           3563     12    99%
+coverage gate: app/ 99% (>90%) OK
+All checks passed!
+0 errors, 0 warnings, 0 informations
+WARNING: there is a new pyright version available (v1.1.411 -> v1.1.414).
+Please install the new version or set PYRIGHT_PYTHON_FORCE_VERSION to `latest`
+
+validation OK

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__03_ls_tree.a1.md

@@ -0,0 +1,11 @@
+All gates green. Task complete — final report:
+
+**Phase 94 · task 03 (drill-down `ls`) — DONE, no commit**
+
+- `app/rag/agent.py`: `ls` branch rewritten to the 3-level tree — `ls_top`/`ls_folder` (+ pure `group_folder_listing`, `render_ls_top`/`render_folder_listing`); new `NOT_A_FOLDER` (parent's subfolders), `LS_PATH_NOT_A_SOURCE` deleted; 50-file cap + grep-pointer note; dead `list_catalog` removed; `AGENT_TOOLS` description pinned.
+- `app/rag/prompts.py`: TOOLS_SECTION drill-down teaching (read/grep clauses byte-identical).
+- `app/api/chat.py` + `scripts/agent_realmodel_check.py`: comment/script repointed off the deleted accessor.
+- Tests: unit (agent/prompts/mock-flow) + integration (real-DB tree, cap, refusals, ordering) rewritten; 5 E2E suites updated for the drill frame (git_sources TRUNCATE + commit-between-inserts seed ordering — UUID tie-break is random, `added_at` is per-transaction).
+- Gates: `pytest` **1939 passed**; `app/` coverage **99%** (gate >90%); ruff clean; pyright 0 errors; E2E in isolation — document-tools 4✓, unlimited 4✓, harness-aligned 3✓, path-teaching 2✓, big-read 4✓, search 3✓, grep-teaching 2✓.
+
+Next pending: `04_e2e_drilldown.md` (not started).

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__03_ls_tree.a1.validate

@@ -0,0 +1,94 @@
+........................................................................ [  3%]
+........................................................................ [  7%]
+........................................................................ [ 11%]
+........................................................................ [ 14%]
+........................................................................ [ 18%]
+........................................................................ [ 22%]
+........................................................................ [ 25%]
+........................................................................ [ 29%]
+........................................................................ [ 33%]
+........................................................................ [ 37%]
+........................................................................ [ 40%]
+........................................................................ [ 44%]
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+........................................................................ [ 51%]
+........................................................................ [ 55%]
+........................................................................ [ 59%]
+........................................................................ [ 63%]
+........................................................................ [ 66%]
+........................................................................ [ 70%]
+........................................................................ [ 74%]
+........................................................................ [ 77%]
+........................................................................ [ 81%]
+........................................................................ [ 85%]
+........................................................................ [ 89%]
+........................................................................ [ 92%]
+........................................................................ [ 96%]
+...................................................................      [100%]
+=============================== warnings summary ===============================
+.venv/lib/python3.13/site-packages/fastapi/testclient.py:1
+  /var/home/ducoterra/Projects/Personal/brain_of_reese/.venv/lib/python3.13/site-packages/fastapi/testclient.py:1: StarletteDeprecationWarning: Using `httpx` with `starlette.testclient` is deprecated; install `httpx2` instead.
+    from starlette.testclient import TestClient as TestClient  # noqa
+
+-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
+================================ tests coverage ================================
+_______________ coverage: platform linux, python 3.13.13-final-0 _______________
+
+Name                           Stmts   Miss  Cover
+--------------------------------------------------
+app/__init__.py                    1      0   100%
+app/api/__init__.py                0      0   100%
+app/api/auth.py                   52      0   100%
+app/api/chat.py                  178      0   100%
+app/api/chats.py                 110      0   100%
+app/api/config.py                 13      0   100%
+app/api/doc_drafts.py             94      0   100%
+app/api/docs.py                   50      0   100%
+app/api/git_sources.py           229      0   100%
+app/api/health.py                 10      0   100%
+app/api/steering.py               42      0   100%
+app/api/suggestions.py            29      0   100%
+app/api/sync.py                  110      0   100%
+app/api/tokens.py                 28      0   100%
+app/api/ui_settings.py            55      0   100%
+app/config.py                    133      0   100%
+app/core/__init__.py               0      0   100%
+app/core/auth.py                  45      0   100%
+app/core/caching.py              124      0   100%
+app/core/debugging.py             29      2    93%
+app/core/docs_push.py             39      0   100%
+app/core/errors.py                 5      0   100%
+app/core/logging.py               13      0   100%
+app/core/rate_limit.py            44      0   100%
+app/core/security_headers.py      20      0   100%
+app/core/theming.py               38      0   100%
+app/core/tokens.py                33      0   100%
+app/db.py                         21      0   100%
+app/main.py                       66      0   100%
+app/models.py                    124      0   100%
+app/rag/__init__.py                0      0   100%
+app/rag/agent.py                 306      1    99%
+app/rag/archive_upload.py        128      0   100%
+app/rag/chunker.py               206      4    98%
+app/rag/folder_summaries.py      110      0   100%
+app/rag/git_sources.py            14      0   100%
+app/rag/importer.py              190      3    98%
+app/rag/llm.py                   217      0   100%
+app/rag/overview.py               71      0   100%
+app/rag/prompts.py                88      0   100%
+app/rag/retriever.py             150      3    98%
+app/rag/scaffolding.py            55      0   100%
+app/rag/source_removal.py         41      0   100%
+app/rag/sources_meta.py           16      0   100%
+app/rag/suggestions.py            27      0   100%
+app/rag/summarizer.py             24      0   100%
+app/schemas.py                   269      0   100%
+--------------------------------------------------
+TOTAL                           3647     13    99%
+coverage gate: app/ 99% (>90%) OK
+All checks passed!
+0 errors, 0 warnings, 0 informations
+WARNING: there is a new pyright version available (v1.1.411 -> v1.1.414).
+Please install the new version or set PYRIGHT_PYTHON_FORCE_VERSION to `latest`
+
+validation OK

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__04_e2e_drilldown.a1.md

@@ -0,0 +1,18 @@
+All green. Task complete.
+
+## Report — Phase 94, Task 04 (E2E drill-down story suite)
+
+**Implemented**
+- `tests/e2e/test_ls_tree_drilldown.py` (new, isolated, own module app port 8136): two local temp sources (`alpha` 56 docs incl. a 51-file `wide/` folder, `beta` 2 docs) registered via the authenticated API + real in-process `POST /api/sync`; pins the 6 stored `folder_summaries` rows byte-exactly (mock's canned `FOLDER_SUMMARY_MODE` text)
+- 3 tests: 4-turn scripted drill `ls()` → `ls(alpha)` → `ls(alpha/two)` → `read(alpha/two/two-a.md)` (tool lines, wire `tool` frames, exact tree levels incl. summaries + file-line format, grounded citations); 51-file cap (exactly 50 lines + `…and 1 more…` note, 51st absent); NOT-A-FOLDER teaching + scripted recovery
+- `tests/e2e/mock_llm.py`: new `DRILL_TRIGGER` scripted flow (question carries its own call: `drill down the tree: ls [target]` / `read source/path`) — tool call → echo the listing verbatim into the answer (house lens); recovery branch keys on receiving the NOT-A-FOLDER line; ALREADY_IN_CONTEXT branch answers from the `<documents>` block
+
+**Results**
+- `uv run pytest tests/e2e/test_ls_tree_drilldown.py -v --no-cov` → 3 passed (in isolation, re-run twice)
+- Regression gate in isolation: `test_agent_document_tools`, `test_agent_unlimited_tools`, `test_harness_aligned_tools`, `test_search_tool`, `test_grep_regex_teaching`, `test_sync_button`, `test_local_directory_sources`, `test_response_to_docs` → all exit 0, 0 failures
+- `uv run pytest --cov=app --cov-report=term-missing` → 1939 passed, app coverage 99% (>90%)
+- `uv run ruff check .` → all checks passed; `uv run pyright` → 0 errors
+
+**Notable decision**: the read target (its path is named in the question) deterministically ranks top-2, so the agent's phase-72 dedupe returns `ALREADY_IN_CONTEXT`; the mock then answers from the `<documents>` prompt with the same citation shape (prefixed `Already in context:`), which the suite pins — the document citation contract holds and the dedupe notice's visibility is asserted.
+
+**Next pending task**: `.agents/phases/todo/94_ls_tree_drilldown/05_realmodel_battery.md`

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__04_e2e_drilldown.a1.validate

@@ -0,0 +1,94 @@
+........................................................................ [  3%]
+........................................................................ [  7%]
+........................................................................ [ 11%]
+........................................................................ [ 14%]
+........................................................................ [ 18%]
+........................................................................ [ 22%]
+........................................................................ [ 25%]
+........................................................................ [ 29%]
+........................................................................ [ 33%]
+........................................................................ [ 37%]
+........................................................................ [ 40%]
+........................................................................ [ 44%]
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+........................................................................ [ 51%]
+........................................................................ [ 55%]
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+........................................................................ [ 63%]
+........................................................................ [ 66%]
+........................................................................ [ 70%]
+........................................................................ [ 74%]
+........................................................................ [ 77%]
+........................................................................ [ 81%]
+........................................................................ [ 85%]
+........................................................................ [ 89%]
+........................................................................ [ 92%]
+........................................................................ [ 96%]
+...................................................................      [100%]
+=============================== warnings summary ===============================
+.venv/lib/python3.13/site-packages/fastapi/testclient.py:1
+  /var/home/ducoterra/Projects/Personal/brain_of_reese/.venv/lib/python3.13/site-packages/fastapi/testclient.py:1: StarletteDeprecationWarning: Using `httpx` with `starlette.testclient` is deprecated; install `httpx2` instead.
+    from starlette.testclient import TestClient as TestClient  # noqa
+
+-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
+================================ tests coverage ================================
+_______________ coverage: platform linux, python 3.13.13-final-0 _______________
+
+Name                           Stmts   Miss  Cover
+--------------------------------------------------
+app/__init__.py                    1      0   100%
+app/api/__init__.py                0      0   100%
+app/api/auth.py                   52      0   100%
+app/api/chat.py                  178      0   100%
+app/api/chats.py                 110      0   100%
+app/api/config.py                 13      0   100%
+app/api/doc_drafts.py             94      0   100%
+app/api/docs.py                   50      0   100%
+app/api/git_sources.py           229      0   100%
+app/api/health.py                 10      0   100%
+app/api/steering.py               42      0   100%
+app/api/suggestions.py            29      0   100%
+app/api/sync.py                  110      0   100%
+app/api/tokens.py                 28      0   100%
+app/api/ui_settings.py            55      0   100%
+app/config.py                    133      0   100%
+app/core/__init__.py               0      0   100%
+app/core/auth.py                  45      0   100%
+app/core/caching.py              124      0   100%
+app/core/debugging.py             29      2    93%
+app/core/docs_push.py             39      0   100%
+app/core/errors.py                 5      0   100%
+app/core/logging.py               13      0   100%
+app/core/rate_limit.py            44      0   100%
+app/core/security_headers.py      20      0   100%
+app/core/theming.py               38      0   100%
+app/core/tokens.py                33      0   100%
+app/db.py                         21      0   100%
+app/main.py                       66      0   100%
+app/models.py                    124      0   100%
+app/rag/__init__.py                0      0   100%
+app/rag/agent.py                 306      1    99%
+app/rag/archive_upload.py        128      0   100%
+app/rag/chunker.py               206      4    98%
+app/rag/folder_summaries.py      110      0   100%
+app/rag/git_sources.py            14      0   100%
+app/rag/importer.py              190      3    98%
+app/rag/llm.py                   217      0   100%
+app/rag/overview.py               71      0   100%
+app/rag/prompts.py                88      0   100%
+app/rag/retriever.py             150      3    98%
+app/rag/scaffolding.py            55      0   100%
+app/rag/source_removal.py         41      0   100%
+app/rag/sources_meta.py           16      0   100%
+app/rag/suggestions.py            27      0   100%
+app/rag/summarizer.py             24      0   100%
+app/schemas.py                   269      0   100%
+--------------------------------------------------
+TOTAL                           3647     13    99%
+coverage gate: app/ 99% (>90%) OK
+All checks passed!
+0 errors, 0 warnings, 0 informations
+WARNING: there is a new pyright version available (v1.1.411 -> v1.1.414).
+Please install the new version or set PYRIGHT_PYTHON_FORCE_VERSION to `latest`
+
+validation OK

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__05_realmodel_battery.a1.md

@@ -0,0 +1,18 @@
+Task 05 complete — all green.
+
+**Implemented**
+- Fixture dump refreshed: `load_test_kb` now generates sync-time folder summaries against live `lite` (4 rows: 2 source roots + `homelab/containers` + `homelab/networking`) and carries `folder_summaries` in TRUNCATE/INSERT/round-trip verify; `restore_test_kb` reports them — restore 0.03 s hot
+- Fixed stale gate-side mirror: `classify_call` now scores `ls(source/folder)` drill-downs as contract-correct (mirrors task-03's resolution rules; previously the correct new behavior would have been flagged)
+- Ran the 10-turn battery against the live endpoint, both models: configured `turbo` (verdict) and `lite` (same-model check vs the phase-70/72 standing, `.env` switched then restored byte-identical)
+- Recorded the dated phase-94 section in `TOOL_CALLING_TESTING.md` (per-turn lines, verdicts, baseline table, conclusion) + moved Q1/2/3/10 expected-behavior notes with the owner-permitted surface (questions untouched) + §2/§5/§8 notes
+
+**Results**
+- turbo: `PASS … calls 18/19 executed (95%) contract 19/19 (100%) (wall 98.7s)` — vs 112.8–113.7 s baseline: −12.5…−13.2 %, within band
+- lite: `PASS … contract 18/18 (100%) (wall 43.6s)` — vs 40.4–40.5 s standing: +7.7 %, within band; no copy-lever iteration needed
+- `uv run pytest --cov=app` → rc=0 (1939 passed, 2 skipped), TOTAL 99 %; `uv run ruff check .` clean; `uv run pyright` 0 errors
+
+**Decisions**
+- Verdict run uses the configured model (`turbo`); `lite` run added for the same-model comparison the task's "phase 70/72 numbers" reference implies — both recorded
+- Flagged for the owner (not a gate miss): `lite` answered the two "list everything" turns from the top level alone; lever noted in §9 if file-level depth is wanted
+
+**Next pending task:** `95_read_truncation_cap/01_read_cap.md`

.agents/reports/94_ls_tree_drilldown/94_ls_tree_drilldown__05_realmodel_battery.a1.validate

@@ -0,0 +1,94 @@
+........................................................................ [  3%]
+........................................................................ [  7%]
+........................................................................ [ 11%]
+........................................................................ [ 14%]
+........................................................................ [ 18%]
+........................................................................ [ 22%]
+........................................................................ [ 25%]
+........................................................................ [ 29%]
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+........................................................................ [ 40%]
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+........................................................................ [ 51%]
+........................................................................ [ 55%]
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+........................................................................ [ 63%]
+........................................................................ [ 66%]
+........................................................................ [ 70%]
+........................................................................ [ 74%]
+........................................................................ [ 77%]
+........................................................................ [ 81%]
+........................................................................ [ 85%]
+........................................................................ [ 89%]
+........................................................................ [ 92%]
+........................................................................ [ 96%]
+...................................................................      [100%]
+=============================== warnings summary ===============================
+.venv/lib/python3.13/site-packages/fastapi/testclient.py:1
+  /var/home/ducoterra/Projects/Personal/brain_of_reese/.venv/lib/python3.13/site-packages/fastapi/testclient.py:1: StarletteDeprecationWarning: Using `httpx` with `starlette.testclient` is deprecated; install `httpx2` instead.
+    from starlette.testclient import TestClient as TestClient  # noqa
+
+-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
+================================ tests coverage ================================
+_______________ coverage: platform linux, python 3.13.13-final-0 _______________
+
+Name                           Stmts   Miss  Cover
+--------------------------------------------------
+app/__init__.py                    1      0   100%
+app/api/__init__.py                0      0   100%
+app/api/auth.py                   52      0   100%
+app/api/chat.py                  178      0   100%
+app/api/chats.py                 110      0   100%
+app/api/config.py                 13      0   100%
+app/api/doc_drafts.py             94      0   100%
+app/api/docs.py                   50      0   100%
+app/api/git_sources.py           229      0   100%
+app/api/health.py                 10      0   100%
+app/api/steering.py               42      0   100%
+app/api/suggestions.py            29      0   100%
+app/api/sync.py                  110      0   100%
+app/api/tokens.py                 28      0   100%
+app/api/ui_settings.py            55      0   100%
+app/config.py                    133      0   100%
+app/core/__init__.py               0      0   100%
+app/core/auth.py                  45      0   100%
+app/core/caching.py              124      0   100%
+app/core/debugging.py             29      2    93%
+app/core/docs_push.py             39      0   100%
+app/core/errors.py                 5      0   100%
+app/core/logging.py               13      0   100%
+app/core/rate_limit.py            44      0   100%
+app/core/security_headers.py      20      0   100%
+app/core/theming.py               38      0   100%
+app/core/tokens.py                33      0   100%
+app/db.py                         21      0   100%
+app/main.py                       66      0   100%
+app/models.py                    124      0   100%
+app/rag/__init__.py                0      0   100%
+app/rag/agent.py                 306      1    99%
+app/rag/archive_upload.py        128      0   100%
+app/rag/chunker.py               206      4    98%
+app/rag/folder_summaries.py      110      0   100%
+app/rag/git_sources.py            14      0   100%
+app/rag/importer.py              190      3    98%
+app/rag/llm.py                   217      0   100%
+app/rag/overview.py               71      0   100%
+app/rag/prompts.py                88      0   100%
+app/rag/retriever.py             150      3    98%
+app/rag/scaffolding.py            55      0   100%
+app/rag/source_removal.py         41      0   100%
+app/rag/sources_meta.py           16      0   100%
+app/rag/suggestions.py            27      0   100%
+app/rag/summarizer.py             24      0   100%
+app/schemas.py                   269      0   100%
+--------------------------------------------------
+TOTAL                           3647     13    99%
+coverage gate: app/ 99% (>90%) OK
+All checks passed!
+0 errors, 0 warnings, 0 informations
+WARNING: there is a new pyright version available (v1.1.411 -> v1.1.414).
+Please install the new version or set PYRIGHT_PYTHON_FORCE_VERSION to `latest`
+
+validation OK

.env.example

@@ -36,6 +36,7 @@ BOR_STEERING_MAX_CHARS=8000       # char budget for the <tuning> (steering notes
 BOR_SUMMARY_MAX_CHARS=12000       # cap on document content sent to the lite summary model (phase 30)
 BOR_KB_OVERVIEW_MAX_CHARS=4000    # char budget for the <knowledge_base> prompt section (phase 31)
 BOR_OVERVIEW_INPUT_MAX_CHARS=40000 # cap on the document list sent to the lite model for the KB outline (phase 31)
+BOR_FOLDER_SUMMARY_INPUT_MAX_CHARS=8000 # cap on a folder's document list sent to the lite model (phase 94)
 BOR_CHUNK_TARGET_CHARS=2000
 BOR_CHUNK_OVERLAP_CHARS=200
 BOR_EMBED_BATCH_SIZE=16

TOOL_CALLING_TESTING.md

@@ -127,14 +127,21 @@ state is snapshotted to **`tests/fixtures/test_kb.dump.sql`** — a
 data-only SQL script (TRUNCATE + one multi-row INSERT per app table:
 documents, chunks + embeddings, the `git_sources` local rows that make
 the source registry self-contained, the static KB overview, the
-sources version). Restoring it puts the whole known state back in one
+sources version, and — since the 2026-09-11 phase-94 refresh — the
-transaction; the generated `chunks.tsv` column is recomputed by
+sync-time `folder_summaries` rows the drill-down `ls` shows). The
-Postgres. The dump is verified by round-trip at build time (restore +
+build generates those rows against the live `lite` endpoint through
-per-table checksum compare — a serialization bug fails the build).
+the real sync-time generator (4 rows for this KB: the two source
+roots + `homelab/containers` + `homelab/networking` — the ≥ 2-document
+folders; single-document folders carry no row by design). Restoring it
+puts the whole known state back in one transaction; the generated
+`chunks.tsv` column is recomputed by Postgres. The dump is verified by
+round-trip at build time (restore + per-table checksum compare — a
+serialization bug fails the build).
 
 ```bash
 # Rebuild the KB + dump — only when the fixture documents, the
-# chunker, or the embedding model change. NOT part of the loop.
+# chunker, the embedding model, or the folder-summary prompt change
+# (its `lite` output is baked in — phase 94). NOT part of the loop.
 uv run python -m scripts.load_test_kb
 # restores the fixture KB standalone (what --restore runs inline)
 uv run python -m scripts.restore_test_kb
@@ -170,22 +177,31 @@ of it.
 
 | # | question | tests | expected ideal |
 |---|---|---|---|
-| 1 | List the files in this directory. | the phase-72 incident; full listing needs `ls` (8 docs, 2 in seed) | `ls()` |
+| 1 | List the files in this directory. | the phase-72 incident; the top level lists the sources — a full file listing drills them (phase 94) | `ls()` → drill `ls('deployments')` + `ls('homelab')` (+ leaf folders) |
-| 2 | List the documents you have in the homelab source. | scoped `ls` by the correct source name | `ls(path='homelab')` |
+| 2 | List the documents you have in the homelab source. | scoped `ls` by the correct source name; the result is the source's folders (+ counts/summaries) — file lines come from the leaf drills (phase 94) | `ls(path='homelab')` (+ leaf drills) |
-| 3 | List every document you have indexed. | no-arg listing | `ls()` |
+| 3 | List every document you have indexed. | the "list everything" expectation is now the whole tree — no single call lists every file (phase 94) | `ls()` → drill both sources and every folder |
 | 4 | Open the document homelab/networking/vela-bridges.md … | `read`, combined form | `read('homelab/networking/vela-bridges.md')` |
 | 5 | Read deployments/quadlet/mimir-service.md and summarize it. | `read`, unseeded target | `read(…)` (or `ls` first, then `read`) |
 | 6 | Open the document homelab/networking/meridian-notes.md … | `read`, unseeded target | `read(…)` |
 | 7 | Find the exact string "rbm-8842" in your documents … | `grep`, pattern only | `grep(pattern='rbm-8842')` — the match line alone answers it |
 | 8 | Which document has the title "Lab Ansible Inventory"? Summarize it. | title lookup; target IS seeded | answer from context (or `ls`) |
 | 9 | What do you know about the qwen 3.8 llama.cpp setup? … | topic lookup; target IS seeded | answer from context |
-| 10 | List the files in the deployments directory. | source name phrased as a directory | `ls(path='deployments')` |
+| 10 | List the files in the deployments directory. | source name phrased as a directory; the result is the source's folders — file lines come from the leaf drills (phase 94) | `ls(path='deployments')` (+ leaf drills) |
 
 Questions 4–6 name the **full combined identity** (no bare-path trap —
 that is the job of the locked derived battery, §6). Questions 7–9 name
 content, so their target document is seeded; the correct behavior
 there is to **not** re-read what is already in the prompt.
 
+Phase-94 note: the listing questions' (1, 2, 3, 10) correct behavior
+**moved with the owner-permitted `ls` surface change** (2026-09-10,
+`TODO.md` L4 — `00_phase.md` of `94_ls_tree_drilldown`): a full file
+listing is now a drill sequence (`ls()` → source → folder; one level
+per call, the old whole-KB flood is structurally gone), and a folder
+line's count + sync-time summary is the tree's picture of that
+subtree. The questions themselves are unchanged (the methodology's
+locked battery) — only the expected-behavior definition moved.
+
 ### The four pass conditions
 
 1. all 10 turns answer (no `LLMError`/`MalformedReplyError`);
@@ -205,10 +221,11 @@ gate: lite PASS turns=10 answered=10 caps=0 tool-turns=10 calls 8/13 executed (6
 gate: lite PASS turns=10 answered=10 caps=0 tool-turns=10 calls 7/11 executed (64%)  contract 11/11 (100%)  (wall 46.8s)
 gate: lite PASS turns=10 answered=10 caps=0 tool-turns=9 calls 9/12 executed (75%) contract 11/12 (92%) 2026-09-06 (wall 40.4s)
 gate: lite PASS turns=10 answered=10 caps=0 tool-turns=10 calls 9/14 executed (64%) contract 13/14 (93%) 2026-09-06 (wall 40.5s)
+gate: lite PASS turns=10 answered=10 caps=0 tool-turns=9 calls 13/18 executed (72%) contract 18/18 (100%) 2026-09-11 (wall 43.6s)   [phase-94 ls tree]
 ```
 
-Contract accuracy ≥ 90 %: **met** (100 / 92 / 100 / 93 / 92 / 93). The executed
+Contract accuracy ≥ 90 %: **met** (100 / 92 / 100 / 93 / 92 / 93 / 100). The
-ratio sits at 58–73 % for the reason documented in §5 — an app
+executed ratio sits at 58–73 % for the reason documented in §5 — an app
 semantics choice, not a model defect, and the open design question in
 §7.
 
@@ -222,6 +239,7 @@ gate: turbo FAIL turns=10 answered=10 caps=0 tool-turns=5 calls 5/5 executed (10
 gate: turbo PASS turns=10 answered=10 caps=0 tool-turns=7 calls 9/9 executed (100%) contract 9/9 (100%) 2026-09-06 (wall 113.7s)
 gate: turbo PASS turns=10 answered=10 caps=0 tool-turns=7 calls 7/7 executed (100%) contract 7/7 (100%) 2026-09-06 (wall 112.8s)
 gate: turbo FAIL turns=10 answered=10 caps=0 tool-turns=5 calls 5/5 executed (100%) contract 5/5 (100%) 2026-09-06 (wall 97.2s)   [derived battery — MISS: 5/10 tool-turn floor]
+gate: turbo PASS turns=10 answered=10 caps=0 tool-turns=7 calls 18/19 executed (95%) contract 19/19 (100%) 2026-09-11 (wall 98.7s)   [phase-94 ls tree]
 ```
 
 Reads: the re-read habit is model-specific. `lite` re-reads a seeded
@@ -304,7 +322,12 @@ The verdict carries both:
   combined `source/path` belongs, a nonexistent document identity, a
   source name where a document belongs (`ls(path='.')`,
   `ls(path='/')`, `grep(path='homelab')` — the entire phase-72
-  incident class).
+  incident class). Phase 94 moved the `ls` contract (owner-permitted
+  surface revision): `ls(path)` is ALSO contract-correct for an
+  EXISTING `source/folder` — the drill-down; the violation is now an
+  unknown first segment, a bare folder name (no source prefix), or a
+  folder matching no indexed prefix. The gate-side mirror
+  (`classify_call` in `scripts/agent_realmodel_check.py`) follows.
 - **executed/emitted** (the phase-72 locked metric) = calls the app
   actually executed ÷ emitted. Every refusal class counts against it
   — **including `ALREADY_IN_CONTEXT`**, the app's dedupe refusal when
@@ -394,7 +417,8 @@ podman compose up -d db
 cp .env.example .env                # once; LLM endpoint + DB URL
 uv run alembic upgrade head
 
-# 1. Build the controlled KB + dump (one-off, ~2 s — real embeddings)
+# 1. Build the controlled KB + dump (one-off, ~7 s — real embeddings +
+#    4 live-lite folder-summary calls since phase 94)
 uv run python -m scripts.load_test_kb
 #    → prints the retrieval report (all 10 must be grounded) and
 #      verifies the dump by round-trip.
@@ -421,3 +445,147 @@ Diagnosing a bad run: every call is logged by `run_agent`
 refusal templates in `app/rag/agent.py` to see which teaching line the
 model hit, and which refusal class (contract violation vs. in-context
 dedupe) the rejection was.
+
+---
+
+## 9. Phase 94 — the `ls` drill-down tree (2026-09-11)
+
+Phase 94 rebuilt `ls` as a drill-down tree (owner-permitted
+tool-surface revision, `TODO.md` L4 — the `ls` result format and
+`path` semantics changed; the tool name and the `read`/`grep`
+contract are untouched): `ls()` lists the synced sources with a
+per-source sync-time summary, `ls(source)` lists its folders (each
+with its summary) + its own files, `ls(source/folder)` drills one
+level deeper; file lines are capped at 50 with a grep pointer. This
+section is the controlled battery's verdict on that architecture —
+the TODO's gate: "ensure accuracy and performance aren't too badly
+impacted", read per the phase-94 task file as **accuracy at or above
+the recorded baseline** (no contract/verdict regression on the
+10-question battery) and **wall time within ~20% of the baseline
+total**.
+
+**Fixture dump refresh (a precondition of this run).** The 2026-09-04
+dump predates migration 0017 — it had no `folder_summaries` rows, so
+the drill-down's summaries would have been absent from the controlled
+KB. It was rebuilt on 2026-09-11 with
+`uv run python -m scripts.load_test_kb`: the same 8 hand-written
+documents through the real pipeline (real embeddings), the static KB
+overview + sources version re-stored, and the sync-time folder
+summaries generated against the live `lite` endpoint (4 rows: the two
+source roots + `homelab/containers` + `homelab/networking` — the
+≥ 2-document folders). The dump now carries the `folder_summaries`
+table (TRUNCATE + INSERT + round-trip checksum verification — the
+house rule); `--restore` measured **0.03 s** hot.
+
+**The classifier mirror followed the surface.** `classify_call`
+(`scripts/agent_realmodel_check.py`) is documented as the gate-side
+mirror of `app.rag.agent._execute_tool`'s resolution rules — task 03
+changed the `ls` resolution (a `source/folder` path is now valid) but
+the mirror still flagged every folder drill-down as a contract
+violation. Fixed in this phase: `ls(path)` is contract-correct for
+`""`, a registered source, or an EXISTING `source/folder`; without
+the fix the battery would have scored the *correct* new behavior as
+inaccurate. (No battery question changed; the §3 expected-behavior
+notes moved with the owner-permitted surface.)
+
+**The runs.** Against the live aipi endpoint, the refreshed fixture
+KB, the real grounded path — two models: the **configured** chat
+model (`turbo` per `.env` — the verdict) and `lite` (the `.env` model
+temporarily switched, then restored byte-identical — the house
+procedure of the 2026-09-05 turbo comparison) to check the
+phase-70/72 standing block, which was recorded under `lite`. The
+micro-loop (`--turns 3` — the three listing turns) ran twice on
+`turbo` first: 12/12 and 13/13 contract (100 %), zero caps — so the
+full battery went straight to the verdict, with no copy-lever
+iteration needed (the first full run on each model was green).
+
+```
+$ uv run python -m scripts.agent_realmodel_check --restore --mode fixture
+restore: ok in 0.03s (8 docs, 2 sources)
+turn 01 | emitted=1 executed=1 cap=no defl=no |  6.80s | List the files in this directory.
+turn 02 | emitted=3 executed=3 cap=no defl=no |  9.77s | List the documents you have in the …
+turn 03 | emitted=7 executed=7 cap=no defl=no | 14.83s | List every document you have indexed.
+turn 04 | emitted=0 executed=0 cap=no defl=no |  8.89s | Open the document …
+turn 05 | emitted=1 executed=1 cap=no defl=no | 12.48s | Read …
+turn 06 | emitted=1 executed=1 cap=no defl=no | 10.03s | Open the document …
+turn 07 | emitted=1 executed=1 cap=no defl=no |  6.85s | Find the exact string "rbm-8842" in …
+turn 08 | emitted=0 executed=0 cap=no defl=no |  7.92s | Which document has the title "Lab …
+turn 09 | emitted=0 executed=0 cap=no defl=no | 10.90s | What do you know about the qwen 3.8 …
+turn 10 | emitted=5 executed=4 cap=no defl=no | 10.08s | List the files in the deployments …
+gate: turbo PASS turns=10 answered=10 caps=0 tool-turns=7 calls 18/19 executed (95%) contract 19/19 (100%) 2026-09-11 (wall 98.7s)
+```
+
+```
+(same command; `.env` chat model temporarily `lite`, restored after)
+turn 01 | emitted=1 executed=1 cap=no defl=no |  3.82s | List the files in this directory.
+turn 02 | emitted=8 executed=5 cap=no defl=no | 10.93s | List the documents you have in the …
+turn 03 | emitted=1 executed=1 cap=no defl=no |  2.25s | List every document you have indexed.
+turn 04 | emitted=1 executed=0 cap=no defl=no |  3.84s | Open the document …
+turn 05 | emitted=3 executed=3 cap=no defl=no |  4.99s | Read …
+turn 06 | emitted=1 executed=1 cap=no defl=no |  5.64s | Open the document …
+turn 07 | emitted=1 executed=1 cap=no defl=no |  2.25s | Find the exact string "rbm-8842" in …
+turn 08 | emitted=1 executed=0 cap=no defl=no |  5.09s | Which document has the title "Lab …
+turn 09 | emitted=0 executed=0 cap=no defl=no |  2.93s | What do you know about the qwen 3.8 …
+turn 10 | emitted=1 executed=1 cap=no defl=no |  1.75s | List the files in the deployments …
+gate: lite PASS turns=10 answered=10 caps=0 tool-turns=9 calls 13/18 executed (72%) contract 18/18 (100%) 2026-09-11 (wall 43.6s)
+```
+
+**Per-turn reading.** Both runs show the designed drill-down: the
+listing turns hop `ls()` → source → folder (turbo turn 03: top level
++ both sources + five leaf folders in 7 calls; lite turn 02:
+`ls('homelab')` + all three homelab folders), the read turns keep the
+combined `source/path` form (turbo turn 05 drills
+`ls('deployments')` → `ls('deployments/quadlet')` before the read —
+the "or `ls` first, then `read`" branch), the grep turn is
+pattern-only, and the seeded discipline turns (04/08/09) answer from
+the `<documents>` context. Zero cap hits, zero contract violations,
+10/10 answered on both models. The non-executed emitted calls are all
+contract-correct (the contract is 100 %): turbo's one (turn 10) is a
+second call in a single reply that the one-tool-per-reply rule
+discards; lite's five are the same discard class (three on turn 02)
+plus the two documented copy-invariant `ALREADY_IN_CONTEXT` re-reads
+of seeded documents (turns 04/08 — §4: 15/15 across every copy
+variant tried). lite turn 02 also carried one exploratory
+`grep(pattern='homelab')` (pattern-only — contract-correct, executed,
+then the proper folder drills in the following rounds — the same
+self-correcting exploration class §5 documents pre-94).
+
+**Baseline comparison.** Against the last recorded baseline per model
+(the 2026-09-06 runs for `turbo`; the phase-70/72 standing block for
+`lite`):
+
+| model | baseline wall | phase-94 wall | Δ wall | baseline contract | phase-94 contract |
+|---|---|---|---|---|---|
+| `turbo` (configured — the verdict) | 112.8–113.7 s | 98.7 s | −12.5 % to −13.2 % | 100 % (7/7, 9/9) | 100 % (19/19) |
+| `lite` (phase-70/72 standing) | 40.4–40.5 s | 43.6 s | +7.7–7.9 % | 92–100 % (last: 92 / 93) | 100 % (18/18) |
+
+Both inside the ~20 % band — `turbo` *under* its same-model baseline
+despite executing MORE calls (18 vs 7–9: the drill-down adds rounds,
+but per-round latency was lower on this day than on the baseline runs
+— wall is endpoint-load-sensitive, which is why a band, not a point,
+is the bar), `lite` +7.7 % — the modest increase the task file
+expects from a few extra `ls` hops. Accuracy: contract at or above
+the same-model baseline on both models; verdict PASS on both; the
+executed ratios (95 % / 72 %) sit in the documented bands (§4/§5 —
+discard class + app-semantics, not tool-calling errors).
+
+**Conclusion.** The phase-94 gate is **met**: accuracy at or above
+baseline (100 % contract, PASS, zero cap hits, zero contract
+violations — on both models) and wall time within the 20 % band on
+both models (−12.5/−13.2 % same-model `turbo`, +7.7 % `lite`
+standing). The phase-72 incident class is gone under the tree: the
+flood is structurally impossible (one level per call, 50-line cap)
+and the listing turns drill cleanly with the folder summaries doing
+the steering. No copy-lever change was made (nothing regressed to
+iterate on).
+
+**Observation for the owner (not a gate miss).** The top level now
+carries the two source summaries, and on the `lite` run the two
+"list everything" turns (01, 03) answered after a single `ls()` —
+from the source-level lines — without drilling to the files; `turbo`
+drilled (3 / 7 calls on the same turns). The gate measures
+contract/verdict, which is met either way; if the owner wants
+listing answers to reach the file level by default, the lever is the
+`ls` description / `TOOLS_SECTION` copy (teach that a folder's file
+lines appear only after drilling into it) — flagged here rather than
+acted on unilaterally.

alembic/versions/0017_folder_summaries.py

@@ -0,0 +1,63 @@
+"""folder_summaries: sync-time lite folder summaries (phase 94, task 01)
+
+Revision ID: 0017
+Revises: 0016
+Create Date: 2026-09-10
+
+Phase 94 (``ls`` becomes a filesystem-style drill-down tree — TODO.md
+L4): the LLM lists the synced projects, then drills into folders; each
+level's listing shows the folder's **subtree summary** — a 1–3 sentence
+plain-text description of what the folder's documents cover, generated
+at sync time by the aipi ``lite`` model (the ``KB_OVERVIEW_MODE``
+contract, ``app.rag.overview``: change-gated by the caller, fail-soft,
+``FOLDER_SUMMARY_MODE`` marker for the E2E mock). This migration adds
+the storage — ONE additive, fully reversible table (A13), no other
+schema change:
+
+* ``folder_summaries`` — one row per folder with ≥ 2 documents
+  (recursive count — the same set the ``ls`` count rule counts,
+  ``00_phase.md``; the ≥ 2 rule and the prune rule are generator
+  policy, ``app.rag.folder_summaries``, not schema constraints):
+
+  * PK ``(source, folder_path)`` — ``source`` is VARCHAR(120) NOT NULL
+    (mirrors ``documents.source``); ``folder_path`` is VARCHAR(1000)
+    NOT NULL (mirrors ``documents.path`` — the source-relative folder
+    prefix). ``folder_path = ""`` is the SOURCE ROOT: the top-level
+    source summary (the whole source's recursive subtree).
+  * ``summary`` — TEXT NOT NULL: the ``lite``-written description
+    (never empty — the generator validates before storing).
+  * ``updated_at`` — TIMESTAMPTZ NOT NULL, server default now() (house
+    style — the ``kb_overview.updated_at`` precedent); the generator
+    always stamps it explicitly on upsert.
+"""
+from __future__ import annotations
+
+import sqlalchemy as sa
+
+from alembic import op
+
+revision = "0017"
+down_revision = "0016"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "folder_summaries",
+        sa.Column("source", sa.String(length=120), primary_key=True),
+        sa.Column("folder_path", sa.String(length=1000), primary_key=True),
+        sa.Column("summary", sa.Text(), nullable=False),
+        sa.Column(
+            "updated_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+    )
+
+
+def downgrade() -> None:
+    # The table is the only 0017 artefact — dropping it leaves the 0016
+    # schema byte-identical (A13, fully reversible).
+    op.drop_table("folder_summaries")

app/api/chat.py

@@ -618,10 +618,10 @@ async def chat(
                 )
                 return
             except Exception:  # noqa: BLE001 — a tool call hit the DB mid-stream
-                # Phase 37: tool execution (list_catalog / find_document)
+                # Phase 37: tool execution (the drill-down ``ls`` /
-                # runs inside the stream now; a mid-turn DB failure gets
+                # ``read`` / ``grep`` lookups) runs inside the stream
-                # the same structured ``error`` event as the pre-stream
+                # now; a mid-turn DB failure gets the same structured
-                # retrieval path.
+                # ``error`` event as the pre-stream retrieval path.
                 logger.exception(
                     "chat: tool execution failed question=%r total_ms=%d",
                     request.message,

app/api/sync.py

@@ -41,7 +41,16 @@ decisions):
    (pruning covers the union; the CLI's no-prune default is unchanged);
 5. when the import changed the KB (added + updated > 0),
    ``regenerate_overview`` refreshes the single ``kb_overview`` row
-   (phase 31 trigger, best-effort inside);
+   (phase 31 trigger, best-effort inside) — and ``generate_
+   folder_summaries`` (phase 94, task 02) regenerates the stored folder
+   summaries (the drill-down ``ls``'s per-level descriptions): its gate
+   is the same change trigger **plus** an empty ``folder_summaries``
+   table (the first sync after migration 0017 — the KB may predate the
+   table). It is per-folder fail-soft (a ``lite`` outage keeps the
+   failed folders' previous rows and never flips the run to
+   ``failed``) and only flushes — this run's own short-lived session
+   commits (the phase-53 convention), so a folder failure never blocks
+   step 6's bump;
 6. when the import changed the KB (added + updated + pruned > 0 — the
    saved-chat invalidation gate, phase 53 task 02: a pruned document
    can invalidate a saved answer that cited it, deliberately broader
@@ -79,6 +88,7 @@ from app.config import get_settings
 from app.core.auth import require_admin
 from app.core.errors import sanitize_error as _sanitize_error
 from app.db import SessionLocal
+from app.rag.folder_summaries import folder_summary_table_empty, generate_folder_summaries
 from app.rag.git_sources import effective_sources
 from app.rag.importer import ImportSummary, import_sources
 from app.rag.llm import LLMClient, check_models
@@ -251,6 +261,26 @@ async def _run_sync() -> None:
         overview = False
         if summary.added + summary.updated > 0:
             overview = await regenerate_overview(llm)
+        # Phase 94 (task 02): the folder summaries — the drill-down
+        # ls's per-level descriptions. Same change gate as the overview
+        # (added + updated > 0), plus the table-empty first-run trigger
+        # (the first sync after migration 0017 — the KB may have been
+        # imported by the CLI before the table landed). The generator is
+        # per-folder fail-soft (a lite outage never flips the run to
+        # failed) and only flushes: this run's own short-lived session
+        # commits (the phase-53 convention), so the step-6 bump stays
+        # change-gated on the KB, not on the summaries. No status-surface
+        # change: the stats are log-only (the detail shape is untouched).
+        fs_db = SessionLocal()
+        try:
+            if summary.added + summary.updated > 0 or folder_summary_table_empty(fs_db):
+                folder_stats = await generate_folder_summaries(fs_db, llm)
+                fs_db.commit()
+                logger.info("sync: folder_summaries stats=%s", folder_stats)
+            else:
+                logger.info("sync: folder_summaries skipped (KB unchanged)")
+        finally:
+            fs_db.close()
         # Phase 53 (task 02): a sync that changed the KB advances the
         # sources version exactly once — the saved-chat invalidation
         # marker (task 03 stamps rows against it). The gate is

app/config.py

@@ -135,6 +135,14 @@ class Settings(BaseSettings):
     #: ``app.rag.overview``). Overflow is cut at the cap and the shared
     #: ``[…truncated…]`` marker is appended (summarizer convention).
     overview_input_max_chars: int = 40_000
+    #: Cap on the folder document list (path/title/first summary line per
+    #: row) sent to the ``lite`` folder-summary model in ONE call
+    #: (phase 94, ``app.rag.folder_summaries``). Overflow is cut at the
+    #: cap and the shared ``[…truncated…]`` marker is appended
+    #: (summarizer convention). Smaller than the KB-overview cap on
+    #: purpose: a folder sees its own subtree only — there can be
+    #: hundreds of folders, each summarized separately at sync time.
+    folder_summary_input_max_chars: int = 8_000
     #: Hard cap on the agent tool rounds per grounded turn (phase 45,
     #: revising phase 37's per-tool budgets — owner permission
     #: 2026-08-27, TODO L8: "allow the LLM to make as many tool calls

app/models.py

@@ -63,6 +63,10 @@ Data model — see ``.agents/PLAN.md`` §Data Model:
                       (``id = 1``); every column NULL = "use the
                       default" (env value for the strings, the built-in
                       palette for the colors — task 01).
+* ``folder_summaries`` — one row per folder with ≥ 2 documents:
+                      the sync-time ``lite`` summary the drill-down
+                      ``ls`` shows next to each folder (phase 94;
+                      ``folder_path = ""`` = the source root).
 """
 from __future__ import annotations
 
@@ -446,3 +450,51 @@ class UiSettings(Base):
     accent_bg: Mapped[str | None] = mapped_column(String(7), nullable=True)
     accent_ink: Mapped[str | None] = mapped_column(String(7), nullable=True)
     accent_line: Mapped[str | None] = mapped_column(String(7), nullable=True)
+
+
+class FolderSummary(Base):
+    """One sync-time folder summary (phase 94, task 01).
+
+    ``ls`` is a drill-down tree (phase 94, ``00_phase.md``): the top
+    level lists the synced projects, each with its stored source-root
+    summary; drilling into a source lists its folders, each with its
+    stored folder summary. This table holds those summaries:
+
+    * PK ``(source, folder_path)`` — ``source`` mirrors
+      ``documents.source`` (String(120)); ``folder_path`` mirrors
+      ``documents.path`` (String(1000)) and is the source-relative
+      folder prefix. ``folder_path = ""`` is the SOURCE ROOT — the
+      top-level source summary (the whole source's recursive subtree).
+    * Rows exist only for folders with ≥ 2 documents (recursive count
+      — the same set the ``ls`` count rule counts): a
+      single-document folder is fully described by its one file line,
+      so no ``lite`` burn. After a changed sync, rows whose folder
+      dropped below 2 documents are pruned (a pruned/renamed folder's
+      summary would otherwise go stale); rows for folders that still
+      have ≥ 2 documents persist (an unchanged folder's summary is
+      still true). Both rules are generator policy (``app.rag.
+      folder_summaries``), not schema constraints.
+    * ``summary`` — the 1–3 sentence plain-text description the aipi
+      ``lite`` model wrote at sync time (``FOLDER_SUMMARY_MODE``,
+      ``app.rag.folder_summaries`` — change-gated and fail-soft like
+      the KB overview: an old summary is better than none).
+
+    Chat turns only READ these rows (the agent's ``ls`` output, phase
+    94 task 03) — generation happens at sync time only (task 02).
+    """
+
+    __tablename__ = "folder_summaries"
+
+    #: Mirrors ``documents.source`` (String(120)) — PK part 1.
+    source: Mapped[str] = mapped_column(String(120), primary_key=True)
+    #: Mirrors ``documents.path`` (String(1000)) — the source-relative
+    #: folder prefix; ``""`` = the source root. PK part 2.
+    folder_path: Mapped[str] = mapped_column(String(1000), primary_key=True)
+    #: The lite-written 1–3 sentence description — never empty (the
+    #: generator validates before storing, ``app.rag.folder_summaries``).
+    summary: Mapped[str] = mapped_column(Text)
+    #: Fresh UTC stamp on every upsert (the ``kb_overview.updated_at``
+    #: precedent; the generator always sets it explicitly).
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), onupdate=func.now()
+    )

app/rag/agent.py

@@ -1,5 +1,6 @@
 """Agent loop: the grounded-turn document tools (phase 37, task 03; the
-harness-aligned ``ls``/``read``/``grep`` surface, phase 70).
+harness-aligned ``ls``/``read``/``grep`` surface, phase 70; the
+drill-down tree ``ls`` + sync-time folder summaries, phase 94).
 
 Probe verdict (task 01 — ``uv run python -m scripts.llm_probe --tools``
 run live against aipi): **``probe: turbo tool_calls=supported 2026-08-26``**
@@ -48,14 +49,41 @@ task 04):
    split (with its self-correction and "teach the split" refusals) is
    gone — the model's combined form is now simply correct. The
    phase-68 A5 match/output contract rides along under the new name.
+   Phase 94 revision (owner permission 2026-09-10, ``TODO.md`` L4 — the
+   tool-surface revision recorded in the phase 94 overview ``00_phase.md``;
+   PLAN.md is being redone by the owner): the ``ls`` RESULT format and
+   ``path`` semantics changed — ``ls`` is now a filesystem-style
+   drill-down tree (no path: the synced sources with counts + stored
+   source-root summaries; a source name: its top-level folders + files;
+   a ``source/folder`` path: that folder's subfolders + files — the
+   model drills one level per call instead of flooding the whole
+   catalog into one result), while the tool NAME and the
+   ``read``/``grep`` contract (combined ``source/path``) are untouched.
 2. Each tool call the model emits is executed server-side against
-   Postgres only (no LLM, no network): ``ls`` returns the indexed
+   Postgres only (no LLM, no network): ``ls`` lists ONE level of the
-   catalog — one ``source: X | path: Y | title: Z`` line per document
+   drill-down tree (phase 94, task 03) — no ``path``: every registered
-   (phase 63: labeled fields — unambiguous for LLM parsing),
+   source (registry order; a 0-document source still lists) as
-   ``GET /api/docs`` order (uncapped in v1; the UI never shows it, only
+   ``{source} — {n} documents`` plus the indented stored source-root
-   the model does) — optionally scoped to one source name (a ``path``
+   summary line when one is in ``folder_summaries``; a ``path`` that is
-   argument matching no source name is a refusal; a registered source
+   a registered source name (no ``/``): that source's root folder —
-   with no indexed documents lists as ``0 documents:`` and counts) —
+   each direct subfolder ``  {sub}/ — {m} documents[: {summary}]``
+   (the count is the subfolder's recursive subtree — every document
+   whose path equals the folder or starts with ``folder + "/"``, the
+   same set the sync-time folder summary describes — and the file
+   lines ``source: X | path: Y | title: Z`` (the canonical
+   ``read``/``grep`` identity — the phase-63 labeled format,
+   unchanged) in path order (``GET /api/docs`` order), capped at
+   :data:`LS_MAX_FILE_LINES` lines + one deterministic grep-pointer
+   note for the rest (a 500-file folder costs 50 lines, never 500);
+   a ``source/folder`` ``path``: that folder's subfolders + own file
+   lines (the same template, ``identity = source + "/" + folder``);
+   a registered source with no documents lists its header line alone
+   (``… — 0 documents, 0 folders:`` — the old ``0 documents:``
+   behavior preserved in spirit) — every successful listing (top/root/
+   folder) counts; a ``source/…`` argument whose first segment names no
+   registered source is the no-source refusal (below, the segment
+   echoed), and a folder segment matching no indexed prefix is the
+   :data:`NOT_A_FOLDER` teaching (below) —
    ``read`` takes the combined ``source/path`` string, splits it at the
    FIRST ``'/'`` (source names are directory basenames — they can never
    contain ``'/'``), and returns the document's **full** content
@@ -82,15 +110,19 @@ task 04):
    blank or non-string) → ``"read requires a string argument
    'path'."``; a ``grep`` without a usable ``pattern`` (missing, blank
    or non-string) → ``"grep requires a string argument
-   'pattern'."``; a scoped ``ls`` whose (stripped) ``path`` contains a
+   'pattern'."``; a scoped ``ls`` whose ``path``'s FIRST segment (split
-   ``/`` — a document path where a source name belongs (source names
+   at the first ``/``) names no registered source — a bare unknown
-   are directory basenames and can never contain one; the 2026-09-03
+   name (the 2026-09-03 incident's ``ls(path='.')``) or the source
-   incident's ``ls(path='app/rag/importer.py')``) →
+   segment of a ``source/…`` argument (phase 94: a ``/`` now names a
-   :data:`LS_PATH_NOT_A_SOURCE`, the document-path teaching line with
+   folder, so the phase-72 document-path teaching refusal is deleted)
-   the argument echoed; a scoped ``ls`` whose ``path`` names no
+   → :data:`NO_SOURCE_NOT_A_DIRECTORY`, the
-   registered source (no ``/`` — the incident's ``ls(path='.')``)
+   no-source refusal with the teaching parenthetical appended, the
-   → :data:`NO_SOURCE_NOT_A_DIRECTORY`, the no-source refusal with the
+   segment echoed; a ``source/…`` argument whose folder segment
-   teaching parenthetical appended; a document
+   matches no indexed prefix (the phase-94 existence rule — some
+   indexed path of the source starts with ``folder + "/"``) →
+   :data:`NOT_A_FOLDER`, the drill-down teaching with the argument
+   echoed and the deepest existing ancestor's direct subfolders
+   listed, so the model self-corrects in the next round; a document
    already in context (seed or previously read) →
    :data:`ALREADY_IN_CONTEXT` (phase 72, task 05 gate iteration:
    the line names the correct action — answer from the text already
@@ -164,25 +196,30 @@ needs none either (the tool ran) — the policy keys on the no-calls
 exit only. No model participates in detection or repair: the
 registry + the fixed retry policy are the whole guardrail.
 
-The DB accessors (:func:`list_catalog`, :func:`list_source_names`,
+The DB accessors — the drill-down ``ls`` (:func:`ls_top`,
-:func:`find_document`, :func:`all_documents`) and the
+:func:`ls_folder`; the pure grouping :func:`group_folder_listing` and
-:func:`grep_document` line matcher are module-level functions so unit
+the pure renderers :func:`render_ls_top` /
-tests can monkeypatch them without a database.
+:func:`render_folder_listing` sit next to them),
+:func:`list_source_names`, :func:`find_document`,
+:func:`all_documents` — and the :func:`grep_document` line matcher are
+module-level functions so unit tests can monkeypatch them without a
+database.
 """
 from __future__ import annotations
 
 import json
 import logging
 import re
-from collections.abc import AsyncIterator, Sequence
+from collections.abc import AsyncIterator, Mapping, Sequence
 from dataclasses import dataclass, field
 from typing import Any
 
-from sqlalchemy import select
+from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 
 from app.config import Settings
-from app.models import Document
+from app.models import Document, FolderSummary
+from app.rag.folder_summaries import folder_of
 from app.rag.git_sources import effective_sources
 from app.rag.llm import (
     LLMClient,
@@ -212,9 +249,17 @@ AGENT_TOOLS: list[dict[str, Any]] = [
         "function": {
             "name": "ls",
             "description": (
-                "List the indexed documents as `source: X | path: Y | "
+                "List the knowledge base as a tree, one level at a "
-                "title: Z` lines. Call one tool at a time — wait for "
+                "time. With no path: the synced sources — each with "
-                "this result before your next call."
+                "its document count and a summary of its contents. "
+                "With a source name (no '/'): that source's top-level "
+                "folders and files. With a `source/folder` path: that "
+                "folder's subfolders and files. Folder lines carry a "
+                "summary of what the folder contains. File lines are "
+                "`source: X | path: Y | title: Z` — use the combined "
+                "`source/path` with `read` and `grep`. Call one tool "
+                "at a time — wait for this result before your next "
+                "call."
             ),
             "parameters": {
                 "type": "object",
@@ -222,13 +267,11 @@ AGENT_TOOLS: list[dict[str, Any]] = [
                     "path": {
                         "type": "string",
                         "description": (
-                            "Source name to list one source's documents "
+                            "Optional — a source name (e.g. "
-                            "(e.g. 'homelab') — a source name, not a "
+                            "'homelab') to list its top level, or a "
-                            "file or directory path; omit to list "
+                            "`source/folder` path to drill down "
-                            "every document. This is the only tool "
+                            "(e.g. 'homelab/active'). Omit it to list "
-                            "whose `path` is a source name — for "
+                            "every source."
-                            "`read` and `grep` it must be a document's "
-                            "combined `source/path`."
                         ),
                     }
                 },
@@ -338,21 +381,6 @@ UNKNOWN_TOOL = "Unknown tool."
 MISSING_READ_ARGS = "read requires a string argument 'path'."
 MISSING_SEARCH_ARGS = "grep requires a string argument 'pattern'."
 
-#: Teaching refusal for a scoped ``ls`` whose stripped ``path``
-#: contains a ``/`` (phase 72): a source name is a directory basename
-#: and can never contain one, so the argument is a document path passed
-#: where a source name belongs (the 2026-09-03 incident's
-#: ``ls(path='app/rag/importer.py')``). One ``{path}`` field — the
-#: argument echoed; a fixed template states the correct contract
-#: instead of the terse pre-phase-72 line, so the harness-prior misuse
-#: self-corrects in one round.
-LS_PATH_NOT_A_SOURCE = (
-    "'{path}' looks like a document path, not a source name. The "
-    "'path' argument of ls filters by source name (e.g. 'homelab') — "
-    "omit it to list every document, or read a document by its "
-    "combined 'source/path' string."
-)
-
 #: The no-source ``ls`` refusal with the teaching parenthetical
 #: appended (phase 72): used when a stripped scope has no ``/`` and
 #: matches no registered source (the incident's ``ls(path='.')``). The
@@ -394,6 +422,29 @@ NO_DOCUMENT_DID_YOU_MEAN_MANY = (
 #: dropped).
 SUGGESTION_LIMIT = 3
 
+#: The drill-down ``ls`` file-line cap (phase 94, task 03): a folder's
+#: own files list at most this many ``source: X | path: Y | title: Z``
+#: lines (path order), then one deterministic grep-pointer note — a
+#: 500-file folder costs the model 50 lines + the note, never 500.
+#: Pinned module constant (no env var — the phase-94 TODO asks for a
+#: shape change, not a knob; the constant lives next to
+#: :data:`SEARCH_MAX_MATCHES`).
+LS_MAX_FILE_LINES = 50
+
+#: The NOT-A-FOLDER ``ls`` teaching refusal (phase 94, task 03):
+#: a ``source/…`` argument whose folder segment matches no indexed
+#: prefix (the ``00_phase.md`` existence rule — a folder exists iff
+#: some indexed path starts with ``folder + "/"``; a document's own
+#: path is never a folder). Phase-72 teaching style: one line, the
+#: argument echoed (``{arg}``), the DEEPEST existing ancestor's name
+#: (``{parent}`` — the source for a top-level miss, ``source/folder``
+#: for a nested one) and its direct subfolders (``{subfolders}`` —
+#: space-joined ``name/`` entries in path order, so the model
+#: self-corrects in the next round; ``none`` when the ancestor has no
+#: subfolders). Still a refusal: it counts in nothing and consumes a
+#: round (no silent argument normalization).
+NOT_A_FOLDER = "'{arg}' is not a folder — {parent} has: {subfolders}"
+
 #: The harness-owned recovery line (phase 71, task 03) — folded into the
 #: ORIGINAL single system message of the one bounded recovery request
 #: (``system_prompt + "\n" + CORRECTION_INSTRUCTION``; provider-safe,
@@ -507,20 +558,6 @@ def plain_form(pattern: str) -> str:
     return p.strip()
 
 
-def list_catalog(db: Session) -> list[tuple[str, str, str]]:
-    """Every indexed document as ``(source, path, title)``.
-
-    Ordered by ``(source, path)`` — the same order as ``GET /api/docs``.
-    Module-level (not a method) so unit tests can monkeypatch it.
-    """
-    rows = db.execute(
-        select(Document.source, Document.path, Document.title).order_by(
-            Document.source, Document.path
-        )
-    ).all()
-    return [(source, path, title) for source, path, title in rows]
-
-
 def list_source_names(db: Session) -> list[str]:
     """Every registered source name, deduped, in registry order.
 
@@ -546,6 +583,286 @@ def list_source_names(db: Session) -> list[str]:
     return names
 
 
+#: The drill-down ``ls`` fetchers (phase 94, task 03) — module-level so
+#: unit tests can monkeypatch them without a database (the house style:
+#: :func:`ls_top` / :func:`ls_folder` compose them; the pure grouping
+#: :func:`group_folder_listing` and renderers
+#: :func:`render_ls_top` / :func:`render_folder_listing` sit below).
+
+
+def _source_document_counts(db: Session) -> list[tuple[str, int]]:
+    """``(source, document count)`` per indexed source (one grouped
+    query — the top-level ``ls`` counts, phase 94 task 03)."""
+    return [
+        (source, count)
+        for source, count in db.execute(
+            select(Document.source, func.count()).group_by(Document.source)
+        )
+    ]
+
+
+def _source_root_summaries(db: Session) -> list[tuple[str, str]]:
+    """The stored source-root summaries ``(source, summary)``
+    (``folder_path = ""`` — the top-level ``ls`` indented lines, phase
+    94 task 03; absent when never generated)."""
+    return [
+        (source, summary)
+        for source, summary in db.execute(
+            select(FolderSummary.source, FolderSummary.summary).where(
+                FolderSummary.folder_path == ""
+            )
+        )
+    ]
+
+
+def _source_document_rows(db: Session, source: str) -> list[tuple[str, str]]:
+    """``(path, title)`` of every document under *source*, ordered by
+    ``path`` — the one bounded fetch a folder drill level lists (phase
+    94 task 03; one source's paths, not the whole KB)."""
+    return [
+        (path, title)
+        for path, title in db.execute(
+            select(Document.path, Document.title)
+            .where(Document.source == source)
+            .order_by(Document.path)
+        )
+    ]
+
+
+def _source_folder_summaries(db: Session, source: str) -> dict[str, str]:
+    """The stored folder summaries ``{folder_path: summary}`` of one
+    source (phase 94 task 03; includes the ``""`` source-root row when
+    stored)."""
+    return {
+        folder_path: summary
+        for folder_path, summary in db.execute(
+            select(FolderSummary.folder_path, FolderSummary.summary).where(
+                FolderSummary.source == source
+            )
+        )
+    }
+
+
+def ls_top(db: Session) -> list[tuple[str, int, str | None]]:
+    """The top level of the drill-down ``ls`` (phase 94, task 03).
+
+    Every registered source in :func:`list_source_names` order (the
+    registry is the source of truth — a registered source with 0
+    indexed documents still lists, the phase-70/72 invariant) as
+    ``(name, recursive_document_count, source_root_summary)``: the
+    count is the source's whole subtree (all of its documents — the
+    same set its stored summary describes) and the summary is the
+    stored ``folder_summaries`` row for ``(source, "")`` (the source
+    root, phase 94 task 01) or ``None`` when absent. Module-level so
+    unit tests can monkeypatch the fetchers.
+    """
+    names = list_source_names(db)
+    if not names:
+        return []
+    counts = dict(_source_document_counts(db))
+    summaries = dict(_source_root_summaries(db))
+    return [(name, counts.get(name, 0), summaries.get(name)) for name in names]
+
+
+def group_folder_listing(
+    source: str,
+    folder: str,
+    rows: Sequence[tuple[str, str]],
+    summaries: Mapping[str, str],
+) -> tuple[list[tuple[str, int, str | None]], list[tuple[str, str, str]], int]:
+    """One level of the drill-down tree (phase 94, task 03) — pure.
+
+    Given *rows* — the source's ``(path, title)`` pairs in catalog
+    (path) order — and *summaries* (the source's stored
+    ``folder_summaries`` rows: ``folder_path → summary``), the folder
+    level *folder* (source-relative; ``""`` = the source root):
+
+    * **(a) direct subfolders** — the folders whose parent is exactly
+      *folder*, in path order, each
+      ``(sub_path_relative_to_source, recursive_count,
+      summary_or_None)``. A folder is a slash-boundary prefix of at
+      least one indexed path (the ``00_phase.md`` existence rule: a
+      folder ``F`` exists ⟺ some path starts with ``F + "/"`` — a
+      document's OWN path is never a folder); the count is the
+      folder's recursive subtree — every path equal to the folder or
+      starting with ``folder + "/"`` (the same set the sync-time
+      folder summary describes, phase 94 task 01 — one concept end to
+      end).
+    * **(b) direct file lines** — the documents whose folder (the
+      prefix before the last ``/`` —
+      :func:`app.rag.folder_summaries.folder_of`, the shared notion) IS
+      *folder*, in path order (catalog order — the same order
+      ``GET /api/docs`` serves), as ``(source, path, title)`` triples
+      — the canonical ``read``/``grep`` identity, capped at
+      :data:`LS_MAX_FILE_LINES` (the rest fold into the renderer's
+      note; a 500-file folder never costs 500 lines).
+    * **(c) the TOTAL direct-file count** — pre-cap, for the note.
+
+    Pure (no I/O) — unit tests drive the grouping without a database;
+    :func:`ls_folder` is the DB-composing wrapper.
+    """
+    # The source's existing folders: every slash-boundary prefix of an
+    # indexed path (the existence rule's candidate set — a folder is
+    # present iff at least one path starts with ``folder + "/"``).
+    folders: set[str] = set()
+    for path, _title in rows:
+        f = folder_of(path)
+        while f:
+            folders.add(f)
+            f = folder_of(f)
+    # The recursive count per folder — the ``path == folder`` arm (a
+    # document sharing a folder's name) plus the ``startswith
+    # folder + "/"`` arm (the folder's true descendants), one pass per
+    # document.
+    counts: dict[str, int] = {f: 0 for f in folders}
+    for path, _title in rows:
+        if path in folders:
+            counts[path] += 1
+        f = folder_of(path)
+        while f:
+            counts[f] += 1
+            f = folder_of(f)
+    subfolders = [
+        (g, counts[g], summaries.get(g))
+        for g in sorted(g for g in folders if folder_of(g) == folder)
+    ]
+    files = [
+        (source, path, title)
+        for path, title in rows
+        if folder_of(path) == folder
+    ]
+    return subfolders, files[:LS_MAX_FILE_LINES], len(files)
+
+
+def ls_folder(
+    db: Session, source: str, folder: str
+) -> tuple[list[tuple[str, int, str | None]], list[tuple[str, str, str]], int]:
+    """One folder level of the drill-down ``ls`` (phase 94, task 03).
+
+    The source's document rows (:func:`_source_document_rows`) and
+    stored folder summaries (:func:`_source_folder_summaries`) through
+    :func:`group_folder_listing` — the pure grouping the unit tests
+    drive directly. ``folder = ""`` is the source root. Module-level
+    so unit tests can monkeypatch the fetchers.
+    """
+    return group_folder_listing(
+        source,
+        folder,
+        _source_document_rows(db, source),
+        _source_folder_summaries(db, source),
+    )
+
+
+def _folder_exists_in(rows: Sequence[tuple[str, str]], folder: str) -> bool:
+    """The phase-94 folder-existence rule (``00_phase.md``), pure.
+
+    Folder *folder* (source-relative) under a registered source
+    exists ⟺ ``folder == ""`` OR some indexed path starts with
+    ``folder + "/"`` — a document's OWN path is never a folder
+    (nothing starts with ``path + "/"``), so ``ls`` of a file path
+    refuses with :data:`NOT_A_FOLDER` rather than listing.
+    """
+    if not folder:
+        return True
+    prefix = folder + "/"
+    return any(path.startswith(prefix) for path, _title in rows)
+
+
+def _deepest_existing_ancestor(
+    rows: Sequence[tuple[str, str]], folder: str
+) -> str:
+    """The deepest EXISTING folder prefix of a missing *folder* (pure).
+
+    The :data:`NOT_A_FOLDER` refusal's teaching context: the argument's
+    segments are walked from the top; the walk stops at the first
+    segment that is no folder, so the returned prefix is the deepest
+    existing ancestor (``""`` = the source root when the first segment
+    is already the miss) and its direct subfolders are the bounded
+    self-correction list the refusal prints.
+    """
+    parent = ""
+    for part in folder.split("/"):
+        candidate = f"{parent}/{part}" if parent else part
+        if not _folder_exists_in(rows, candidate):
+            break
+        parent = candidate
+    return parent
+
+
+def render_ls_top(entries: Sequence[tuple[str, int, str | None]]) -> str:
+    """The top-level ``ls`` result (phase 94, task 03) — the pinned
+    template.
+
+    ``{N} sources:`` — the line alone when the registry is empty (the
+    old ``0 documents:`` behavior preserved in spirit) — then, when at
+    least one source is registered, a blank line and one block per
+    source in registry order: ``{source} — {n} documents`` plus the
+    indented ``  {summary}`` line ONLY when the source-root summary is
+    stored (absent → the count line alone, no placeholder) — with NO
+    blank line between blocks.
+    """
+    lines = [f"{len(entries)} sources:"]
+    if entries:
+        lines.append("")
+        for source, count, summary in entries:
+            lines.append(f"{source} — {count} documents")
+            if summary:
+                lines.append(f"  {summary}")
+    return "\n".join(lines)
+
+
+def render_folder_listing(
+    identity: str,
+    subfolders: Sequence[tuple[str, int, str | None]],
+    files: Sequence[tuple[str, str, str]],
+    total_files: int,
+) -> str:
+    """One folder level of the drill-down ``ls`` (phase 94, task 03) —
+    the pinned template.
+
+    The header ``{identity} — {n_files} documents, {n_folders}
+    folders:`` (``n_files`` = *total_files*, the PRE-cap direct-file
+    count; ``identity`` is the source name at the root level and
+    ``source/folder`` below it), then — when the level carries anything
+    below the header — a blank line, the 2-space-indented subfolder
+    lines ``  {sub}/ — {m} documents`` in path order (``: {summary}``
+    appended ONLY when the subfolder's summary is stored), a blank
+    line, the file lines in EXACTLY the existing
+    ``source: X | path: Y | title: Z`` format (the canonical
+    ``read``/``grep`` identity — unchanged), and the cap note
+    ``…and {hidden} more documents in this folder — use grep
+    (pattern) to find a specific one.`` ONLY when the folder's own
+    files outnumber :data:`LS_MAX_FILE_LINES` (*files* arrives capped;
+    *total_files* carries the pre-cap count). A header with no
+    subfolders and no files — a registered source with no documents —
+    is the header line alone (``… — 0 documents, 0 folders:``).
+    """
+    header = f"{identity} — {total_files} documents, {len(subfolders)} folders:"
+    if not subfolders and not files:
+        return header
+    body: list[str] = []
+    if subfolders:
+        body.append("")
+        for sub, count, summary in subfolders:
+            line = f"  {sub}/ — {count} documents"
+            if summary:
+                line += f": {summary}"
+            body.append(line)
+    if files or total_files > len(files):
+        body.append("")
+        body.extend(
+            f"source: {source} | path: {path} | title: {title}"
+            for source, path, title in files
+        )
+        hidden = total_files - len(files)
+        if hidden > 0:
+            body.append(
+                f"…and {hidden} more documents in this folder — use grep "
+                "(pattern) to find a specific one."
+            )
+    return "\n".join([header, *body])
+
+
 def find_document(db: Session, source: str, path: str) -> Document | None:
     """The indexed document at ``(source, path)``, or ``None``.
 
@@ -704,30 +1021,61 @@ def _execute_tool(
     phase 70).
     """
     if call.name == "ls":
+        # Phase 94 (task 03): the drill-down tree — one level per call
+        # (the owner-permitted tool-surface revision; the old
+        # whole-catalog listing is gone). A successful listing at ANY
+        # level (top/root/folder) counts; a refusal counts in nothing
+        # and consumes a round like every refusal.
         raw_path = call.arguments.get("path")
         scope = raw_path.strip() if isinstance(raw_path, str) else ""
-        rows = list_catalog(db)
+        if not scope:
-        if scope:
+            # The top level: the synced sources, registry order, each
-            if "/" in scope:
+            # with its recursive document count and its stored
-                # A source name (a directory basename) can never
+            # source-root summary (``None`` → no indented line).
-                # contain '/' — this is a document path where a source
+            holder.tool_calls += 1
-                # name belongs (phase 72): teach the contract; no
+            return render_ls_top(ls_top(db))
-                # registry lookup needed, counts in nothing, consumes
+        source, _, rest = scope.partition("/")
-                # a round like every refusal.
+        if source not in list_source_names(db):
-                return LS_PATH_NOT_A_SOURCE.format(path=scope)
+            # The no-source refusal with the teaching parenthetical
-            if scope not in list_source_names(db):
+            # (phase 72, the prefix byte-identical to the pre-phase-72
-                # The no-source refusal with the teaching parenthetical
+            # line): the FIRST segment is the source candidate — a bare
-                # (phase 72) — the prefix byte-identical to the
+            # unknown name (the incident's ``ls(path='.')``) or the
-                # pre-phase-72 line; counts in nothing, consumes a
+            # source segment of a ``source/…`` argument (phase 94: a
-                # round like every refusal.
+            # ``/`` now names a folder, so the phase-72 document-path
-                return NO_SOURCE_NOT_A_DIRECTORY.format(scope=scope)
+            # teaching is deleted) — the segment echoed; counts in
-            rows = [row for row in rows if row[0] == scope]
+            # nothing, consumes a round like every refusal.
-        listing = f"{len(rows)} documents:\n" + "\n".join(
+            return NO_SOURCE_NOT_A_DIRECTORY.format(scope=source)
-            f"source: {source} | path: {path} | title: {title}"
+        if not rest:
-            for source, path, title in rows
+            # The source's ROOT folder: subfolders + own file lines
-        )
+            # (capped + note) — the pinned template; a registered
+            # source with no documents lists its header line alone
+            # (``… — 0 documents, 0 folders:`` — the old
+            # ``0 documents:`` behavior preserved in spirit).
+            subfolders, files, total = ls_folder(db, source, "")
+            holder.tool_calls += 1
+            return render_folder_listing(source, subfolders, files, total)
+        rows = _source_document_rows(db, source)
+        summaries = _source_folder_summaries(db, source)
+        if not _folder_exists_in(rows, rest):
+            # The NOT-A-FOLDER teaching (phase 94, task 03): the
+            # argument echoed, the DEEPEST existing ancestor's name and
+            # its direct subfolders listed (bounded — the parent's own
+            # listing, so no new flood path), so the model
+            # self-corrects in the next round; counts in nothing,
+            # consumes a round like every refusal.
+            parent = _deepest_existing_ancestor(rows, rest)
+            parent_subs = group_folder_listing(source, parent, rows, summaries)[0]
+            return NOT_A_FOLDER.format(
+                arg=scope,
+                parent=source if not parent else f"{source}/{parent}",
+                subfolders=" ".join(f"{sub}/" for sub, _c, _s in parent_subs)
+                or "none",
+            )
+        # The folder level: the same template as the root, identity =
+        # source + "/" + folder.
+        subfolders, files, total = group_folder_listing(source, rest, rows, summaries)
         holder.tool_calls += 1
-        return listing
+        return render_folder_listing(f"{source}/{rest}", subfolders, files, total)
     if call.name == "read":
         raw_path = call.arguments.get("path")
         arg = raw_path.strip() if isinstance(raw_path, str) else ""

app/rag/folder_summaries.py

@@ -0,0 +1,391 @@
+"""Folder summary generator (phase 94, task 01).
+
+``ls`` becomes a drill-down tree (phase 94, ``00_phase.md``): the LLM
+lists the synced projects, then drills into folders. Each level's
+listing shows the folder's **subtree summary** — a 1–3 sentence
+plain-text description of what the folder's documents cover, generated
+at SYNC time by the aipi ``lite`` model (the ``KB_OVERVIEW_MODE``
+contract of ``app.rag.overview``: change-gated by the caller,
+fail-soft — an old summary is better than none — and E2E-mockable via
+the ``FOLDER_SUMMARY_MODE`` system-prompt marker).
+
+ONE concept end to end (:func:`group_by_folder`): a folder row's
+documents are its **recursive subtree** — every document whose path
+equals the folder or starts with ``folder + "/"`` — exactly the set the
+``ls`` count rule (``00_phase.md``) counts. A document under ``a/b/``
+therefore contributes to the ``a``, ``a/b``, and ``""`` (source root)
+groups alike: each level's listing shows its own accurate subtree
+summary, and the number next to a folder is the number of documents its
+summary describes.
+
+Storage: ``folder_summaries`` (migration 0017) — PK
+``(source, folder_path)``; ``folder_path = ""`` is the SOURCE ROOT
+(the top-level source summary). Rows exist only for folders with
+≥ 2 documents (the :data:`MIN_DOCS_PER_FOLDER` rule — a
+single-document folder is fully described by its one file line, so no
+``lite`` burn); after a changed sync, rows whose folder dropped below
+2 documents are pruned (a pruned/renamed folder's summary would
+otherwise go stale), while rows for folders that still have
+≥ 2 documents persist (an unchanged folder's summary is still true).
+
+Chat turns never generate folder summaries — the agent's ``ls`` output
+(phase 94, task 03) only reads the stored rows. Generation is the
+caller's job at sync time (phase 94, task 02), and :func:`generate_
+folder_summaries` only flushes — the sync path owns the transaction
+(the phase-53 ``bump_sources_version`` convention).
+"""
+from __future__ import annotations
+
+import logging
+from collections.abc import Sequence
+from datetime import UTC, datetime
+from typing import Protocol
+
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+
+from app.config import Settings, get_settings
+from app.models import Document, FolderSummary
+from app.rag.llm import LLMError
+from app.rag.retriever import TRUNCATION_MARKER
+
+logger = logging.getLogger("app.rag.folder_summaries")
+
+#: System-prompt marker for folder-summary generation — the E2E mock
+#: LLM keys on it (same convention as ``SUMMARY_MODE`` /
+#: ``KB_OVERVIEW_MODE``, PLAN §6).
+FOLDER_SUMMARY_MODE = "FOLDER_SUMMARY_MODE"
+
+#: Locked instruction for the ``lite`` model (phase 94): the folder
+#: summary is the drill-down ``ls``'s per-level picture, so it must be
+#: a short plain-text description of what the folder's documents
+#: cover — 1–3 sentences (a folder is a skim, not a read: the document
+#: summary's 3–6 sentences would blow up a 20-folder listing),
+#: strictly grounded in the listed titles/paths/summary lines.
+FOLDER_SUMMARY_INSTRUCTION = (
+    "From the document list below, write a 1-3 sentence plain-text "
+    "summary of what this folder's documents cover, in natural "
+    "language. Do not use markdown. Do not invent anything that is not "
+    "in the list."
+)
+
+#: Full system prompt: marker first (the mock's key), then the
+#: instruction (the ``app.rag.overview.SYSTEM_PROMPT`` shape).
+SYSTEM_PROMPT = f"{FOLDER_SUMMARY_MODE}: {FOLDER_SUMMARY_INSTRUCTION}"
+
+#: First line of the user message — the folder the summary describes:
+#: ``<source>`` for the source root, ``<source>/<folder_path>`` for a
+#: folder. The deterministic E2E mock keys on it to name the folder in
+#: its canned reply (``tests/e2e/mock_llm.py``), so the stored row is
+#: a pure function of the request.
+FOLDER_HEADER_PREFIX = "Folder: "
+
+#: A folder is summarized only while its recursive subtree holds at
+#: least this many documents — a single-document folder is fully
+#: described by its one file line, so no ``lite`` burn (phase 94
+#: ``00_phase.md`` scope rule; the prune rule applies the same count).
+MIN_DOCS_PER_FOLDER = 2
+
+#: One document row for the grouping/prompting:
+#: ``(source, path, title, summary)`` — the ``app.rag.overview``
+#: ``build_overview_prompt`` row shape (``summary`` is the stored
+#: lite-written text or ``None`` for markdown docs / the fail-soft
+#: path).
+DocRow = tuple[str, str, str, str | None]
+
+
+class FolderSummaryLLM(Protocol):
+    """The one-shot chat surface the folder-summary generator needs.
+
+    :class:`app.rag.llm.LLMClient` satisfies it; unit tests pass a
+    duck-typed fake (``chat`` + ``settings``) instead — same pattern as
+    the overview's ``OverviewLLM`` protocol.
+    """
+
+    settings: Settings
+
+    async def chat(
+        self, messages: list[dict[str, str]], model: str | None = None
+    ) -> str: ...
+
+
+def folder_of(path: str) -> str:
+    """The directory prefix before the last ``/`` (``""`` for root-level files).
+
+    The single notion of "which folder owns this document" used by the
+    whole module: ``folder_of("a.md") == ""``,
+    ``folder_of("a/b.md") == "a"``, ``folder_of("a/b/c.md") == "a/b"``.
+    Iterating :func:`folder_of` over its own result walks a path's
+    folder prefixes from nearest to farthest, ending at ``""``.
+    """
+    idx = path.rfind("/")
+    return path[:idx] if idx >= 0 else ""
+
+
+def group_by_folder(rows: Sequence[DocRow]) -> dict[tuple[str, str], list[DocRow]]:
+    """Group document rows by the folders their recursive subtree fills.
+
+    The ONE concept of this module, documented in the module docstring:
+    a folder row's documents are its **recursive subtree** — every
+    document whose path equals the folder or starts with
+    ``folder + "/"`` — exactly the set the ``ls`` count rule counts.
+    Each row therefore lands in the ``""`` (source root) group AND in
+    the group of every folder prefix of its path: a doc under
+    ``a/b/`` contributes to the ``a``, ``a/b``, and ``""`` groups.
+    Per source the candidate rows are thus ``""`` (all of the source's
+    documents — the top-level source summary) plus every distinct
+    folder prefix of an indexed path.
+
+    *rows* are ``(source, path, title, summary)`` tuples (the
+    :data:`DocRow` shape, e.g. straight from the ``documents``
+    catalogue query). Returns ``{(source, folder_path): [rows]}`` —
+    group lists keep the input (catalogue) order, so downstream prompt
+    building is deterministic. Groups of ANY size (≥ 1) are returned;
+    the ≥ 2 :data:`MIN_DOCS_PER_FOLDER` rule is applied by
+    :func:`generate_folder_summaries`, not here.
+
+    """
+    # Pass 1: the distinct TRUE folder prefixes of the catalogue — a
+    # folder is a slash-boundary prefix of at least one indexed path
+    # (the ``00_phase.md`` candidate definition: ``""`` + every distinct
+    # folder prefix, per source).
+    folders: set[tuple[str, str]] = set()
+    for row in rows:
+        source, path = row[0], row[1]
+        folder = folder_of(path)
+        while folder:
+            folders.add((source, folder))
+            folder = folder_of(folder)
+
+    # Pass 2: every row lands in the source-root group, in the group of
+    # every ancestor folder (the ``startswith folder + "/"`` arm of the
+    # count rule), and — when its path IS one of the source's folder
+    # prefixes (a file sharing its name with a directory) — in that
+    # folder's group too (the ``path == folder`` arm). A row therefore
+    # belongs to its folder's group iff its path equals the folder or
+    # starts with ``folder + "/"`` — exactly the set the ``ls`` count
+    # rule counts, for EVERY group.
+    groups: dict[tuple[str, str], list[DocRow]] = {}
+    for row in rows:
+        source, path = row[0], row[1]
+        groups.setdefault((source, ""), []).append(row)
+        if (source, path) in folders:
+            groups.setdefault((source, path), []).append(row)
+        folder = folder_of(path)
+        while folder:
+            groups.setdefault((source, folder), []).append(row)
+            folder = folder_of(folder)
+    return groups
+
+
+def _first_summary_line(summary: str | None) -> str:
+    """First line of a stored summary, stripped; ``''`` when absent.
+
+    The stored summary (phase 30) ends in the code-appended
+    ``Source: …`` pointer line, so its first line is the model-written
+    lead sentence — the best one-line picture of the document for the
+    folder summary. Blank/whitespace-only summaries yield ``''`` as
+    well (the ``app.rag.overview`` helper, mirrored locally so each
+    lite-mode module stays self-contained).
+    """
+    if not summary:
+        return ""
+    for line in summary.splitlines():
+        stripped = line.strip()
+        if stripped:
+            return stripped
+    return ""
+
+
+def _folder_label(source: str, folder_path: str) -> str:
+    """The user-message folder identifier (the ``FOLDER_HEADER_PREFIX`` tail).
+
+    ``<source>`` for the source root (``folder_path = ""``),
+    ``<source>/<folder_path>`` for a folder — the canonical folder
+    identity the E2E mock echoes into its canned reply.
+    """
+    return source if not folder_path else f"{source}/{folder_path}"
+
+
+def build_folder_summary_prompt(
+    source: str,
+    folder_path: str,
+    docs: Sequence[DocRow],
+    max_chars: int | None = None,
+) -> tuple[str, str]:
+    """The ``(system, user)`` message pair for one folder-summary call.
+
+    * ``system`` — :data:`SYSTEM_PROMPT`: the ``FOLDER_SUMMARY_MODE``
+      marker + the locked instruction.
+    * ``user`` — the folder header line
+      (``FOLDER_HEADER_PREFIX + <source>[/<folder_path>]`` — the line
+      the E2E mock parses to name the folder), then one line per
+      document, ``path — title — {first line of summary}``, joined
+      with newlines, in the given (catalogue) order. The summary field
+      is omitted when the document has none (markdown docs and the
+      fail-soft path — no dangling dash, the overview convention). The
+      whole message is capped at *max_chars* (default
+      ``BOR_FOLDER_SUMMARY_INPUT_MAX_CHARS``): overflow is cut exactly
+      at the cap and the shared ``[…truncated…]`` marker is appended on
+      its own line, so the model never sees more than the cap and the
+      cut is visible (summarizer convention, phase 30).
+    """
+    lines = [FOLDER_HEADER_PREFIX + _folder_label(source, folder_path)]
+    for _source, path, title, summary in docs:
+        line = f"{path} — {title}"
+        first = _first_summary_line(summary)
+        if first:
+            line += f" — {first}"
+        lines.append(line)
+    user = "\n".join(lines)
+    limit = (
+        max_chars
+        if max_chars is not None
+        else get_settings().folder_summary_input_max_chars
+    )
+    if len(user) > limit:
+        user = user[:limit] + "\n" + TRUNCATION_MARKER
+    return SYSTEM_PROMPT, user
+
+
+async def summarize_folder(
+    source: str, folder_path: str, docs: Sequence[DocRow], llm: FolderSummaryLLM
+) -> str:
+    """One-shot ``lite`` summary of one folder's recursive subtree.
+
+    Builds the prompt from the folder's documents (each ``path``,
+    ``title``, first summary line), makes ONE :meth:`LLMClient.chat`
+    call against ``llm.settings.llm_summary_model`` (the ``lite``
+    model — no new model management), and returns the model's text
+    trimmed. Raises :class:`LLMError` when the reply is empty after
+    trimming (the client already rejects empty content; re-asserted
+    defensively, the summarizer's rule — a silent summary must never be
+    stored), and propagates any :class:`LLMError` the client raises
+    (the generator's fail-soft path catches it per folder).
+    """
+    system, user = build_folder_summary_prompt(source, folder_path, docs)
+    raw = await llm.chat(
+        [{"role": "system", "content": system}, {"role": "user", "content": user}],
+        model=llm.settings.llm_summary_model,
+    )
+    summary = raw.strip()
+    if not summary:
+        label = _folder_label(source, folder_path)
+        raise LLMError(
+            f"folder summary model returned empty content for {label} — "
+            "refusing to store a silent summary"
+        )
+    return summary
+
+
+def _upsert(db: Session, source: str, folder_path: str, summary: str) -> None:
+    """Insert or update the row for one folder (fresh UTC stamp)."""
+    now = datetime.now(UTC)
+    row = db.get(FolderSummary, (source, folder_path))
+    if row is None:
+        db.add(
+            FolderSummary(
+                source=source, folder_path=folder_path, summary=summary, updated_at=now
+            )
+        )
+    else:
+        row.summary = summary
+        row.updated_at = now
+
+
+def folder_summary_table_empty(db: Session) -> bool:
+    """Whether ``folder_summaries`` holds no rows (the sync-path gate).
+
+    Phase 94 (task 02): the ``_overview_row_exists`` pattern
+    (``scripts.import_docs``) extended to a table-emptiness check —
+    after an unchanged re-sync, an EMPTY table (the first full sync
+    after migration 0017, or after a ``--limit`` debug walk that
+    skipped generation) still gets a fresh batch, while a populated
+    table is left untouched until the KB actually changes. One
+    bounded ``LIMIT 1`` probe, never a count scan.
+    """
+    return db.execute(select(FolderSummary.source).limit(1)).first() is None
+
+
+async def generate_folder_summaries(
+    db: Session, llm: FolderSummaryLLM, *, skip: bool = False
+) -> dict[str, int]:
+    """Regenerate the stored folder summaries for the current catalogue.
+
+    The sync-path orchestrator (phase 94, task 02 calls it
+    change-gated, like the KB overview; ``--limit`` debug runs pass
+    ``skip=True``). Steps, in order:
+
+    1. ``skip=True`` → a no-op: the zero stats dict is returned, the
+       LLM is never called, and no rows are touched.
+    2. Group the document catalogue by :func:`group_by_folder` (the
+       recursive-subtree concept) and keep the candidate folders —
+       the ones whose recursive subtree holds
+       :data:`MIN_DOCS_PER_FOLDER` (≥ 2) documents. Single-document
+       folders get no row (their one file line IS their summary).
+    3. For each candidate (deterministic ``(source, folder_path)``
+       order) call :func:`summarize_folder` and UPSERT — fail-soft PER
+       FOLDER: one folder's :class:`LLMError` is logged and counted,
+       its previous row (if any) is kept, and the remaining folders
+       still land (a ``lite`` outage must never fail the sync — the KB
+       is the product, the summaries are auxiliary).
+    4. DELETE rows whose folder no longer has ≥ 2 documents — a
+       pruned/renamed folder's summary goes stale and is dropped.
+       Rows for folders that still qualify persist (regenerated in
+       step 3 — an unchanged folder's summary is still true).
+
+    Only flushes — the CALLER commits (the phase-53
+    ``bump_sources_version`` convention: the sync path owns the
+    transaction, so a failed sync rolls the summaries back with it).
+
+    Returns the small stats dict ``{"generated", "failed", "pruned"}``
+    for the caller's summary-line logging (PLAN §9 ample logging).
+    """
+    stats = {"generated": 0, "failed": 0, "pruned": 0}
+    if skip:
+        return stats
+
+    result = db.execute(
+        select(Document.source, Document.path, Document.title, Document.summary)
+        .order_by(Document.source, Document.path)
+    ).all()
+    rows: list[DocRow] = [
+        (source, path, title, summary)
+        for source, path, title, summary in result
+    ]
+    groups = group_by_folder(rows)
+    candidates = {
+        key: docs for key, docs in groups.items() if len(docs) >= MIN_DOCS_PER_FOLDER
+    }
+
+    for source, folder_path in sorted(candidates):
+        docs = candidates[(source, folder_path)]
+        try:
+            summary = await summarize_folder(source, folder_path, docs, llm)
+        except LLMError as e:
+            stats["failed"] += 1
+            logger.error(
+                "folder summary failed for %s/%s — %s", source, folder_path, e
+            )
+            continue
+        _upsert(db, source, folder_path, summary)
+        stats["generated"] += 1
+
+    existing = db.execute(
+        select(FolderSummary.source, FolderSummary.folder_path)
+    ).all()
+    for source, folder_path in existing:
+        if (source, folder_path) not in candidates:
+            row = db.get(FolderSummary, (source, folder_path))
+            if row is not None:
+                db.delete(row)
+                stats["pruned"] += 1
+
+    db.flush()
+    logger.info(
+        "folder_summaries: generated=%d failed=%d pruned=%d",
+        stats["generated"],
+        stats["failed"],
+        stats["pruned"],
+    )
+    return stats

app/rag/prompts.py

@@ -31,7 +31,15 @@ name*, not a directory or file path, and ``read``/``grep`` take the
 combined ``source/path`` string *including the source name* (a bare
 document path will not resolve) — the same two things the phase-72
 teaching refusals in :mod:`app.rag.agent` re-state after the fact, so
-the model carries the contract before it calls a tool): the **HIGH**
+the model carries the contract before it calls a tool; phase 94,
+task 03: the ``ls`` clause is rewritten to the drill-down tree
+contract — no ``path``: the synced sources with counts + summaries, a
+source name: its top-level folders + files, a ``source/folder`` path:
+one level deeper — a listing shows only that level's subfolders + own
+files (never the whole KB in one call), the folder summaries say
+what's in a folder before drilling, and ``grep`` stays the locator for
+finding one document without listing; the ``read``/``grep`` clauses
+and the discipline rules are byte-identical): the **HIGH**
 prompt only carries a ``<tools>`` section after the ``<documents>``
 body — the grounded turn may extend its context through the three
 server-side tools (round-capped, see :mod:`app.rag.agent`; the cap is
@@ -103,7 +111,17 @@ _KB_INTRO = (
 #: ``path`` is a *source name* (not a directory or file path) and
 #: ``read``/``grep`` take the combined ``source/path`` string *including
 #: the source name* (a bare document path will not resolve) — the same
-#: two things the phase-72 teaching refusals re-state after the fact):
+#: two things the phase-72 teaching refusals re-state after the fact;
+#: phase 94, task 03 — the owner-permitted tool-surface revision,
+#: recorded in the phase 94 overview: the ``ls`` clause is rewritten
+#: to the drill-down tree contract — no ``path``: the synced sources
+#: with counts + summaries, a source name: its top-level folders +
+#: files, a ``source/folder`` path: one level deeper — a listing shows
+#: only that level's subfolders + own files, never the whole KB in one
+#: call, the folder summaries say what's in a folder before drilling,
+#: and ``grep`` stays the locator for finding one document without
+#: listing; the ``read``/``grep`` clauses and the discipline rules are
+#: byte-identical):
 #: a grounded turn may extend its context through the three server-side
 #: tools (round cap: ``BOR_AGENT_MAX_ROUNDS`` — the cap is the bound and
 #: this section does not re-state it, phase 45). Appended after the mode
@@ -139,23 +157,30 @@ _KB_INTRO = (
 TOOLS_SECTION: str = (
     "<tools>\n"
     "You may extend your context with three tools. `ls` lists the "
-    "indexed documents as `source: X | path: Y | title: Z` lines; its "
+    "knowledge base as a tree, one level at a time: with no `path` it "
-    "optional `path` argument is a source name (e.g. 'homelab'), not a "
+    "lists every synced source with its document count and a summary "
-    "directory or file path — omit it to list every document. `read` "
+    "of its contents; with a source name (e.g. 'homelab') it lists "
-    "pulls in one document by its combined `source/path` string, "
+    "that source's top-level folders and files; with a `source/folder` "
-    "exactly as shown in the `ls` output — including the source name — "
+    "path it drills one level deeper. A listing shows only that "
-    "adding its full content to your context. Do not call `read` for a "
+    "level's subfolders and its own files — never the whole knowledge "
-    "document already shown in the <documents> section, even when the "
+    "base in one call — and each folder line's summary says what the "
-    "user asks you to open or read it — its full text is already in "
+    "folder contains before you drill into it. File lines are "
-    "your prompt; answer directly from it. For `read`, a bare document "
+    "`source: X | path: Y | title: Z`; to find one specific document "
-    "path (without the source name) will not resolve. `grep` locates an "
+    "without listing, use `grep`. `read` pulls in one document by its "
-    "exact string (case-insensitive) in the indexed documents and "
+    "combined `source/path` string, exactly as shown in the `ls` "
-    "returns up to 20 matching `source/path:line: text` lines — a "
+    "output — including the source name — adding its full content to "
-    "locator, not a context-adder: read the winner with `read`. A grep "
+    "your context. Do not call `read` for a document already shown in "
-    "pattern is a plain substring, NEVER a regex — '.*' and '\\.' are "
+    "the <documents> section, even when the user asks you to open or "
-    "literal text there; if such a pattern returns no matches, retry "
+    "read it — its full text is already in your prompt; answer "
-    "with the plain text you expect to see. For a normal search pass "
+    "directly from it. For `read`, a bare document path (without the "
-    "only `pattern` — its optional `path` argument "
+    "source name) will not resolve. `grep` locates an exact string "
+    "(case-insensitive) in the indexed documents and returns up to 20 "
+    "matching `source/path:line: text` lines — a locator, not a "
+    "context-adder: read the winner with `read`. A grep pattern is a "
+    "plain substring, NEVER a regex — '.*' and '\\.' are literal text "
+    "there; if such a pattern returns no matches, retry with the plain "
+    "text you expect to see. For a normal search pass only `pattern` — "
+    "its optional `path` argument "
     "limits the search to one document you already know, by the same "
     "combined `source/path` string; never a source name — a bare "
     "document path (without the source name) will not resolve there "

scripts/agent_realmodel_check.py

@@ -82,17 +82,18 @@ from pathlib import Path
 from typing import Any
 
 from dotenv import load_dotenv
+from sqlalchemy import select
 
 from app.api.chat import plan_turn
 from app.api.steering import load_steering_notes
 from app.config import Settings, get_settings
 from app.db import SessionLocal, db_available
+from app.models import Document
 from app.rag.agent import (
     CORRECTION_INSTRUCTION,
     AgentHolder,
     MalformedReplyError,
     find_document,
-    list_catalog,
     list_source_names,
     run_agent,
 )
@@ -113,6 +114,19 @@ logger = logging.getLogger("agent_realmodel_check")
 #: Repo-relative fixture dump (written by scripts.load_test_kb).
 DEFAULT_DUMP_PATH = Path("tests/fixtures/test_kb.dump.sql")
 
+
+def _catalog(db) -> list[tuple[str, str, str]]:
+    """The full catalog as ``(source, path, title)`` in ``(source, path)``
+    order — the battery builder's pre-phase-94 ``list_catalog`` contract,
+    kept local to this script (phase 94 deleted the agent accessor: the
+    drill-down ``ls`` lists one bounded source level at a time)."""
+    rows = db.execute(
+        select(Document.source, Document.path, Document.title).order_by(
+            Document.source, Document.path
+        )
+    ).all()
+    return [(source, path, title) for source, path, title in rows]
+
 #: The per-turn line truncates the question at this width (the locked
 #: format prints ``turn NN | emitted=E executed=X cap=Y|N | <question>``).
 QUESTION_DISPLAY_WIDTH = 40
@@ -263,7 +277,7 @@ def check_preconditions(
             return 2
         return None
     with SessionLocal() as db:
-        catalog = list_catalog(db)
+        catalog = _catalog(db)
     if len(catalog) < 2:
         print(
             f"precondition failed: catalog holds {len(catalog)} document(s) "
@@ -443,8 +457,33 @@ async def _run_deflected(
             )
 
 
+def _ls_folder_prefixes(catalog: set[tuple[str, str]]) -> dict[str, set[str]]:
+    """The existing ``ls`` folders per source (the phase-94 drill-down
+    contract): for each source, the set of source-relative folder
+    prefixes — every slash-boundary prefix of its indexed paths.
+
+    Mirrors the ``00_phase.md`` existence rule that
+    ``app.rag.agent._execute_tool`` applies: a folder ``F`` exists ⟺
+    some indexed path of the source starts with ``F + "/"`` — a
+    document's OWN path is never a folder, so the document's path itself
+    is not in the set (``ls`` of a file path is a refusal, as is a bare
+    folder name missing its source prefix).
+    """
+    folders: dict[str, set[str]] = {}
+    for source, path in catalog:
+        folder = path[: path.rfind("/")] if "/" in path else ""
+        while folder:
+            folders.setdefault(source, set()).add(folder)
+            folder = folder[: folder.rfind("/")] if "/" in folder else ""
+    return folders
+
+
 def classify_call(
-    name: str, args: dict[str, Any], catalog: set[tuple[str, str]], sources: set[str]
+    name: str,
+    args: dict[str, Any],
+    catalog: set[tuple[str, str]],
+    sources: set[str],
+    ls_folders: dict[str, set[str]],
 ) -> bool:
     """Contract correctness of ONE emitted call (the tool-calling
     accuracy metric, 2026-09-04 controlled methodology).
@@ -460,12 +499,25 @@ def classify_call(
     re-read 15/15 across copy variants — is documented in
     ``TOOL_CALLING_TESTING.md``). The classification mirrors
     ``app.rag.agent._execute_tool``'s resolution rules gate-side (no
-    app-code changes for measurement).
+    app-code changes for measurement) — including the phase-94 ``ls``
+    revision (owner-permitted tool-surface change, ``00_phase.md``):
+    ``ls(path)`` is contract-correct for ``""`` (the synced sources),
+    a registered source name (its root folder), or a ``source/folder``
+    path naming an EXISTING folder (``ls_folders`` — the drill-down);
+    an unknown first segment, a bare folder name (no source prefix), or
+    a folder matching no indexed prefix is the violation.
     """
     if name == "ls":
         raw = args.get("path")
         scope = raw.strip() if isinstance(raw, str) else ""
-        return scope == "" or scope in sources
+        if not scope:
+            return True  # the top level (the synced sources)
+        source, _, rest = scope.partition("/")
+        if source not in sources:
+            return False  # unknown first segment (the phase-72 incident class)
+        if not rest:
+            return True  # a registered source's root folder
+        return rest in ls_folders.get(source, ())
     if name == "read":
         raw = args.get("path")
         arg = raw.strip() if isinstance(raw, str) else ""
@@ -498,10 +550,13 @@ def score_contract(
     and source names. Per-turn counts are attached on each
     :class:`TurnResult` as ``_contract_ok`` (measurement state, not a
     dataclass field — the display line stays the locked format)."""
+    ls_folders = _ls_folder_prefixes(catalog)
     ok = 0
     for turn in turns:
         turn_ok = sum(
-            1 for name, args in turn.calls if classify_call(name, args, catalog, sources)
+            1
+            for name, args in turn.calls
+            if classify_call(name, args, catalog, sources, ls_folders)
         )
         turn._contract_ok = turn_ok  # type: ignore[attr-defined]
         ok += turn_ok
@@ -763,7 +818,7 @@ def main(argv: list[str] | None = None) -> int:
         )
     else:
         with SessionLocal() as db:
-            catalog = list_catalog(db)
+            catalog = _catalog(db)
             s2, p2, _t2 = catalog[1]
             d2 = find_document(db, s2, p2)
         d2_content = d2.content if d2 is not None else ""
@@ -794,7 +849,7 @@ def main(argv: list[str] | None = None) -> int:
     # source names (the KB is static across the run — the restore, when
     # any, happened before the battery).
     with SessionLocal() as db:
-        catalog_set = set((s, p) for s, p, _t in list_catalog(db))
+        catalog_set = set((s, p) for s, p, _t in _catalog(db))
         sources_set = set(list_source_names(db))
     score_contract(turns, catalog_set, sources_set)
     passed, conditions = evaluate(

scripts/import_docs.py

@@ -54,6 +54,20 @@ reports ``overview=failed`` on the summary line: the import's exit code
 is about files, and the previous outline stays (an old outline is better
 than none).
 
+The stored folder summaries (phase 94 — the drill-down ``ls``'s
+per-level descriptions, the ``folder_summaries`` table) regenerate in
+the same run under the same gate: a changed KB (added + updated > 0),
+or an empty table after an unchanged walk (the first full run after
+migration 0017, or after a ``--limit`` first walk that skipped them).
+Same contract — **best-effort, per-folder fail-soft**: a ``lite``
+failure keeps the failed folders' previous rows and only counts into
+the stats; ``--limit`` debug runs skip them entirely (never burning a
+``lite`` call). The stats land on the summary line as
+``folder_summaries=<generated>/<failed>/<pruned>`` (or
+``folder_summaries=skipped`` when the gate did not fire), and the rows
+commit in the run's own short-lived session (the phase-53 convention —
+a failed commit rolls them back with it).
+
 A run that **changed** the knowledge base (added + updated + pruned > 0
 — phase 53, task 02) also advances the single-row ``sources_meta``
 version exactly once (``sources_version=<n>`` on the summary line): the
@@ -78,6 +92,7 @@ from app.core.debugging import configure_debugging
 from app.core.logging import configure_logging
 from app.db import SessionLocal
 from app.models import KbOverview
+from app.rag.folder_summaries import folder_summary_table_empty, generate_folder_summaries
 from app.rag.git_sources import effective_sources
 from app.rag.importer import ImportSummary, import_sources
 from app.rag.llm import LLMClient
@@ -216,6 +231,20 @@ def _overview_row_exists() -> bool:
         return session.get(KbOverview, 1) is not None
 
 
+def _folder_summaries_table_empty() -> bool:
+    """Whether the ``folder_summaries`` table holds any row (phase 94).
+
+    The ``_overview_row_exists`` pattern extended to a table-emptiness
+    check (one bounded ``LIMIT 1`` probe): an empty table after an
+    unchanged re-import — e.g. the first full run after migration 0017,
+    or after a ``--limit`` first walk that skipped generation — still
+    gets a fresh batch of folder summaries, while a populated table is
+    left untouched until the KB actually changes.
+    """
+    with SessionLocal() as session:
+        return folder_summary_table_empty(session)
+
+
 def main(argv: list[str] | None = None) -> int:
     args = build_parser().parse_args(argv)
     settings = get_settings()
@@ -246,9 +275,10 @@ def main(argv: list[str] | None = None) -> int:
 
     llm = LLMClient()
 
-    async def _run() -> tuple[ImportSummary, str, str]:
+    async def _run() -> tuple[ImportSummary, str, str, dict[str, int] | None]:
-        """Import, then (change-gated) advance the sources version and
+        """Import, then (change-gated) advance the sources version,
-        refresh the stored KB overview.
+        refresh the stored KB overview, and regenerate the stored folder
+        summaries.
 
         One event loop, one ``LLMClient`` (phase 31, task 04): the
         outline that every chat prompt injects as ``<knowledge_base>`` is
@@ -268,6 +298,17 @@ def main(argv: list[str] | None = None) -> int:
         deliberately broader than the overview's). ``--limit`` debug
         runs and unchanged re-runs never bump. The returned token is
         the new version, or ``"skipped"``.
+
+        The folder summaries (phase 94, task 02) follow the same gate
+        — a changed KB, or an empty ``folder_summaries`` table after an
+        unchanged walk (the first full run after migration 0017, or
+        after a ``--limit`` first walk) — with per-folder fail-soft
+        inside the generator (a ``lite`` failure keeps the failed
+        folders' previous rows). The generator only flushes: this
+        run's own short-lived session commits (the phase-53
+        convention), and the stats land on the summary line as
+        ``folder_summaries=<generated>/<failed>/<pruned>``
+        (``None`` — rendered ``skipped`` — when the gate did not fire).
         """
         summary = await import_sources(
             sources, llm, prune=args.prune, limit=args.limit,
@@ -294,32 +335,69 @@ def main(argv: list[str] | None = None) -> int:
             sources_version = "skipped"
             logger.info("sources: version bump skipped (KB unchanged)")
         if args.limit is not None:
+            # An incomplete walk must never rewrite the outline or the
+            # folder summaries (the --limit skip, mirrored above for the
+            # sources version).
             logger.info("overview: skipped (--limit)")
-            return summary, "skipped", sources_version
+            return summary, "skipped", sources_version, None
-        if summary.added + summary.updated == 0:
+        changed = summary.added + summary.updated > 0
+        overview_due = changed
+        folders_due = changed
+        if not changed:
             if summary.files == 0:
                 logger.info("overview: skipped (nothing imported)")
-                return summary, "skipped", sources_version
+                return summary, "skipped", sources_version, None
-            if _overview_row_exists():
+            # The unchanged-walk first-run triggers: the overview when
+            # no row exists yet (the first run after migration 0005),
+            # the folder summaries when the table is empty (the first
+            # full run after migration 0017, or after a --limit first
+            # walk that skipped them).
+            overview_due = not _overview_row_exists()
+            folders_due = _folder_summaries_table_empty()
+            if not overview_due and not folders_due:
                 logger.info("overview: skipped (KB unchanged)")
-                return summary, "skipped", sources_version
+                return summary, "skipped", sources_version, None
-            # No outline yet after an unchanged re-import (e.g. the first
+        overview_status = "skipped"
-            # run after migration 0005) — fall through and generate one.
+        if overview_due:
-        ok = await regenerate_overview(llm)
+            ok = await regenerate_overview(llm)
-        return summary, "updated" if ok else "failed", sources_version
+            overview_status = "updated" if ok else "failed"
+        else:
+            logger.info("overview: skipped (KB unchanged)")
+        # Phase 94 (task 02): the folder summaries — same event loop +
+        # LLMClient (phase 31 convention), per-folder fail-soft inside
+        # the generator (a ``lite`` failure never flips the exit code).
+        # It only flushes — this run's own short-lived session commits
+        # (the phase-53 convention), so a failed commit rolls the
+        # summaries back with it.
+        folder_stats: dict[str, int] | None = None
+        if folders_due:
+            session = SessionLocal()
+            try:
+                folder_stats = await generate_folder_summaries(session, llm)
+                session.commit()
+            finally:
+                session.close()
+        return summary, overview_status, sources_version, folder_stats
 
-    summary, overview_status, sources_version = asyncio.run(_run())
+    summary, overview_status, sources_version, folder_stats = asyncio.run(_run())
+    folder_token = (
+        "skipped"
+        if folder_stats is None
+        else f"{folder_stats['generated']}/{folder_stats['failed']}/{folder_stats['pruned']}"
+    )
     print(
         f"import_docs: files={summary.files} added={summary.added} "
         f"updated={summary.updated} unchanged={summary.unchanged} "
         f"pruned={summary.pruned} errors={summary.errors} chunks={summary.chunks} "
         f"embed_batches={summary.embed_batches} summaries={summary.summaries} "
         f"summary_errors={summary.summary_errors} formats={summary.format_counts()} "
-        f"overview={overview_status} sources_version={sources_version}"
+        f"overview={overview_status} sources_version={sources_version} "
+        f"folder_summaries={folder_token}"
     )
     # Non-zero if any file failed, so cron/CI notice — the rest of the KB
     # was imported and the failed files are retried on the next run. The
-    # overview is best-effort: a failed outline never changes the exit code.
+    # overview and the folder summaries are best-effort: a failed outline
+    # or a failed folder batch never changes the exit code.
     return 1 if summary.errors else 0
 
 

scripts/load_test_kb.py

@@ -15,23 +15,30 @@ guessable by any model. This script:
    ``BOR_GIT_SOURCES`` env var),
 3. imports the fixture documents through the real pipeline
    (``import_sources`` — real chunking + real ``embed``-model
-   embeddings; this is the ONLY step that burns model calls, and only
+   embeddings; this is the only step that burns ``embed`` calls, and
-   at build time),
+   only at build time),
 4. stores the static KB overview + the sources-version row,
-5. prints a **retrieval report** for every fixture-battery question
+5. generates the sync-time **folder summaries** through the real
+   generator (``app.rag.folder_summaries``) against the live ``lite``
+   endpoint — the drill-down ``ls`` (phase 94) shows the stored rows,
+   so the dump must carry them (the build always truncates first, so
+   the sync paths' table-empty first-run trigger holds; a failed batch
+   aborts the build — a summary-less dump would be a broken fixture),
+6. prints a **retrieval report** for every fixture-battery question
    (grounded or deflected, which documents would seed) — the battery
    must be all-grounded for the gate to exercise the tools,
-6. snapshots the resulting database state into
+7. snapshots the resulting database state into
    ``tests/fixtures/test_kb.dump.sql`` — a data-only SQL script
    (TRUNCATE + one multi-row ``INSERT`` per app table, generated
    in-process — the same file runs in psql or psycopg, in one
    transaction) — and **verifies the snapshot by restoring it and
    comparing a per-table checksum**.
 
-Re-run it only when the fixture documents, the chunker, or the
+Re-run it only when the fixture documents, the chunker, the embedding
-embedding model change — everyday iterations restore the dump in
+model, or the folder-summary prompt (its ``lite`` output is baked into
-sub-second time (``scripts/restore_test_kb`` / the gate's
+the dump) change — everyday iterations restore the dump in sub-second
-``--restore``), never re-embedding (see ``TOOL_CALLING_TESTING.md``).
+time (``scripts/restore_test_kb`` / the gate's ``--restore``), never
+re-embedding (see ``TOOL_CALLING_TESTING.md``).
 
 Exit codes: **0** built + verified, **1** build/verification failure,
 **2** precondition failure.
@@ -59,6 +66,7 @@ from app.models import (
     Chunk,
     DocDraft,
     Document,
+    FolderSummary,
     GitSource,
     KbOverview,
     QueryLog,
@@ -66,6 +74,7 @@ from app.models import (
     SourcesMeta,
     SteeringNote,
 )
+from app.rag.folder_summaries import generate_folder_summaries
 from app.rag.importer import import_sources
 from app.rag.llm import LLMClient
 from app.rag.retriever import retrieve
@@ -111,6 +120,12 @@ _TABLES: tuple[tuple[str, type, tuple[str, ...]], ...] = (
     ("doc_drafts", DocDraft, ("id", "token", "title", "path", "body",
                               "status", "branch", "commit_sha", "created_at",
                               "updated_at")),
+    # Phase 94 (task 05): the sync-time folder summaries the drill-down
+    # ``ls`` shows — generated against the live ``lite`` endpoint in
+    # step 5 of :func:`_build` (the build truncates first, so the sync
+    # paths' table-empty first-run trigger holds).
+    ("folder_summaries", FolderSummary, ("source", "folder_path",
+                                         "summary", "updated_at")),
 )
 
 
@@ -257,7 +272,31 @@ async def _build(kb_dir: Path, dump_path: Path) -> int:
         db.add(meta)
         db.commit()
 
-    # 4. Retrieval report (all battery questions must stay grounded).
+    # 4. The sync-time folder summaries (phase 94, task 05): the
+    #    drill-down ``ls`` shows the stored rows, so the dump carries
+    #    them. Generated against the live ``lite`` endpoint through the
+    #    real sync-time generator — the build just truncated the table,
+    #    so the sync paths' table-empty first-run trigger holds (no
+    #    change-gate bookkeeping needed on a fresh build). The generator
+    #    only flushes; this build commits (the phase-53 convention the
+    #    sync paths follow). A failed batch aborts: the dump's folder
+    #    lines are part of the controlled fixture.
+    with SessionLocal() as db:
+        folder_stats = await generate_folder_summaries(db, llm)
+        db.commit()
+    logger.info(
+        "load_test_kb: folder summaries generated=%d failed=%d pruned=%d",
+        folder_stats["generated"], folder_stats["failed"], folder_stats["pruned"],
+    )
+    if folder_stats["failed"]:
+        print(
+            f"load_test_kb: {folder_stats['failed']} folder summary call(s) "
+            "failed — the fixture dump needs the stored rows; check the LLM "
+            "endpoint (BOR_LLM_SUMMARY_MODEL) and re-run"
+        )
+        return 1
+
+    # 5. Retrieval report (all battery questions must stay grounded).
     n_deflected = await _retrieval_report(llm, list(FIXTURE_BATTERY))
     if n_deflected:
         print(
@@ -267,7 +306,7 @@ async def _build(kb_dir: Path, dump_path: Path) -> int:
             "question before running the gate."
         )
 
-    # 5. Snapshot (data-only) + round-trip verification.
+    # 6. Snapshot (data-only) + round-trip verification.
     with SessionLocal() as db:
         before = {table: _table_checksum(db, table) for table, _m, _c in _TABLES}
         parts = [
@@ -309,7 +348,8 @@ async def _build(kb_dir: Path, dump_path: Path) -> int:
     wall = time.monotonic() - started
     print(
         f"load_test_kb: ok — docs={summary.added} chunks={summary.chunks} "
-        f"sources={len(FIXTURE_SOURCES)} dump={dump_path} "
+        f"sources={len(FIXTURE_SOURCES)} folder_summaries={folder_stats['generated']} "
+        f"dump={dump_path} "
         f"({dump_path.stat().st_size // 1024} KB, verified by round-trip) "
         f"in {wall:.1f}s"
     )

scripts/restore_test_kb.py

@@ -11,11 +11,13 @@ snapshot in **one transaction** through the app's own database URL
 (``BOR_DATABASE_URL``): no git clone of the homelab repo, no re-embedding,
 no ``lite``-model calls — the whole known state (documents, chunks +
 embeddings, the source registry rows, the KB overview, the sources
-version) lands in a fraction of a second, which is what makes a
+version, the stored folder summaries — the drill-down ``ls``'s rows,
-tool-calling iteration loop fast (see ``TOOL_CALLING_TESTING.md``):
+phase 94, task 05) lands in a fraction of a second, which is what makes
+a tool-calling iteration loop fast (see ``TOOL_CALLING_TESTING.md``):
 
     uv run python -m scripts.restore_test_kb
-    # restore_test_kb: ok in 0.41s (8 docs, 2 sources, 16 chunks)
+    # restore_test_kb: ok in 0.41s (8 docs, 2 sources, 9 chunks,
+    # 4 folder summaries, dump … KB)
 
 The gate runs the same restore inline:
 ``uv run python -m scripts.agent_realmodel_check --restore``.
@@ -57,6 +59,10 @@ APP_TABLES: tuple[str, ...] = (
     "query_log",
     "saved_chats",
     "doc_drafts",
+    # Phase 94 (task 05): the sync-time folder summaries the drill-down
+    # ``ls`` shows — the dump carries the rows (built by
+    # ``scripts.load_test_kb`` against the live ``lite`` endpoint).
+    "folder_summaries",
 )
 
 #: Repo-relative default dump location (the load script writes it there).
@@ -71,6 +77,7 @@ class RestoreResult:
     docs: int
     sources: tuple[str, ...]
     chunks: int
+    folders: int  # stored folder summaries (phase 94)
     dump_bytes: int
 
 
@@ -127,11 +134,13 @@ def restore_dump(dump: Path) -> RestoreResult:
             )
         )
         chunks = db.execute(text("select count(*) from chunks")).scalar_one()
+        folders = db.execute(text("select count(*) from folder_summaries")).scalar_one()
     return RestoreResult(
         seconds=seconds,
         docs=docs,
         sources=sources,
         chunks=chunks,
+        folders=folders,
         dump_bytes=dump.stat().st_size,
     )
 
@@ -169,7 +178,8 @@ def main(argv: list[str] | None = None) -> int:
     print(
         f"restore_test_kb: ok in {result.seconds:.2f}s "
         f"({result.docs} docs, {len(result.sources)} sources, "
-        f"{result.chunks} chunks, dump {result.dump_bytes // 1024} KB)"
+        f"{result.chunks} chunks, {result.folders} folder summaries, "
+        f"dump {result.dump_bytes // 1024} KB)"
     )
     return 0
 

tests/e2e/mock_llm.py

@@ -18,6 +18,14 @@ Implements just enough of the aipi surface:
   - ``KB_OVERVIEW_MODE`` -> the deterministic outline: the first 8 tokens
     of the user message (the generator puts the document list there) —
     byte-stable for a given KB (KB overview, phase 31)
+  - ``FOLDER_SUMMARY_MODE`` -> the deterministic folder one-liner
+    ``Fixture folder summary for <folder>.`` — <folder> is the user
+    message's ``Folder: …`` header line (the generator names the
+    source/folder there, phase 94), so the stored row always names its
+    folder and an E2E can assert on it. Checked BEFORE the
+    ``SUMMARY_MODE`` branch: the folder marker CONTAINS the summary
+    marker as a substring, so the summary branch would otherwise
+    shadow every folder-summary call
   - ``DEFLECT_MODE``  -> honest "I haven't done anything like that" answer
   - otherwise         -> upbeat answer quoting the provided document context
   - user message containing ``pretend to think slowly`` -> 3s warm-up delay
@@ -57,22 +65,31 @@ Implements just enough of the aipi surface:
     closing tag — same sentinel semantics.)
   - user message containing ``use your tools`` (phase 37, agent document
     tools; phase 70: the flow emits the harness-aligned names — ``ls``
-    / ``read`` with the combined ``source/path`` identity) **and** the
+    / ``read`` with the combined ``source/path`` identity; phase 94:
-    system prompt carries the ``<tools>`` section -> the deterministic
+    the flow DRILLS through the tree ``ls`` — the top-level listing
-    SINGLE-READ tool flow, discriminated statelessly from the messages
+    carries sources only, so the flow takes one drill step, ``ls``
-    (the ``tools`` parameter gates the list/read steps — a no-tools
+    scoped to the first source, before the first file line exists)
-    request with no tool results is not the flow):
+    **and** the system prompt carries the ``<tools>`` section -> the
+    deterministic SINGLE-READ tool flow, discriminated statelessly from
+    the messages (the ``tools`` parameter gates the list/read steps —
+    a no-tools request with no tool results is not the flow):
       * request 1 (``tools`` offered, no tool results yet): stream ONLY
         ``tool_calls`` deltas — ``ls`` (synthetic id ``call_0``, no
         arguments), ``finish_reason: "tool_calls"``, no content;
-      * request 2 (a ``tool``-role catalog result in the messages):
+      * request 2 (the top-level source listing in the messages — the
-        parse the FIRST catalog line (``source: X | path: Y | title: Z``
+        agent's ``ls`` tree format, phase 94: no file lines yet):
-        — the labeled ``source:`` / ``path:`` fields, phase 63) and
+        stream a ``tool_calls`` delta — ``ls`` scoped to the FIRST
-        stream a ``tool_calls`` delta calling ``read`` on the JOINED
+        source of the listing (id ``call_1``) — the drill step (one
-        combined ``source/path`` (the mock joins the two labeled fields
+        drill per flow — ``_drill_target`` skips already-drilled
-        — the catalog format is unchanged, so this join is the only
+        sources, so the second listing is the folder level);
-        parse change, phase 70) (id ``call_1``);
+      * request 3 (a ``tool``-role folder listing with file lines in
-      * request 3 (a ``tool``-role read result in the messages —
+        the messages): parse the FIRST file line (``source: X | path:
+        Y | title: Z`` — the labeled ``source:`` / ``path:`` fields,
+        phase 63) and stream a ``tool_calls`` delta calling ``read`` on
+        the JOINED combined ``source/path`` (the mock joins the two
+        labeled fields — the file-line format is unchanged, so this
+        join is the only parse change, phase 70) (id ``call_2``);
+      * request 4 (a ``tool``-role read result in the messages —
         content starting with the agent's ``"Document <source/path>:"``
         header): a content answer, deterministic: ``Read
         <source/path>. <first 80 chars of the read document's
@@ -85,19 +102,22 @@ Implements just enough of the aipi surface:
   - user message containing BOTH ``use your tools`` AND ``read two
     documents`` (``MULTI_READ_TRIGGER``, phase 45 task 02) **and** the
     system prompt carries the ``<tools>`` section -> the deterministic
-    MULTI-READ flow (list → read #1 → read #2 → answer), classified by
+    MULTI-READ flow (list → drill → read #1 → read #2 → answer; phase
-    the COUNT of ``tool``-role read results (content starting with the
+    94: the drill step between the top-level listing and the first
-    agent's ``"Document <source/path>:"`` prefix); phase 70: the same
+    read), classified by the COUNT of ``tool``-role read results
-    flow on the harness-aligned names — ``ls``, then ``read`` on the
+    (content starting with the agent's ``"Document <source/path>:"``
-    JOINED combined ``source/path`` of each catalog line:
+    prefix); phase 70: the same flow on the harness-aligned names —
-      * 0 read results, no catalog yet: ``ls`` (id ``call_0``);
+    ``ls``, the drill ``ls`` scoped to the first source, then ``read``
-      * 0 read results, catalog present: ``read`` on the JOINED
+    on the JOINED combined ``source/path`` of each file line:
-        combined ``source/path`` of the FIRST catalog line
+      * 0 read results, no listing yet: ``ls`` (id ``call_0``);
-        (id ``call_1``);
+      * 0 read results, top-level listing only (no file lines yet):
+        the drill — ``ls`` scoped to the first source (id ``call_1``);
+      * 0 read results, file lines present: ``read`` on the JOINED
+        combined ``source/path`` of the FIRST file line (id ``call_2``);
       * 1 read result: ``read`` on the JOINED combined ``source/path``
-        of the SECOND catalog line — the first listing line whose
+        of the SECOND file line — the first listing line whose
         ``source/path`` differs from the one already read (id
-        ``call_2``); a one-document catalog degenerates to the
+        ``call_3``); a one-file listing degenerates to the
         single-read answer (nothing second to read);
       * 2 read results: the forced answer, byte-stable: the single-read
         shape quoting the FIRST read result, plus the line ``I read
@@ -162,27 +182,83 @@ Implements just enough of the aipi surface:
     misuse met the terse refusal and the model re-reasoned the same
     paragraphs over and over) **and** the system prompt carries the
     ``<tools>`` section -> the deterministic LS-TEACHING flow,
-    discriminated statelessly from the messages (streaming only):
+    discriminated statelessly from the messages (streaming only;
+    phase 94: the correction's top-level listing carries sources only,
+    so the flow drills one level before the first file line exists):
       * request 1 (``tools`` offered, no ``tool``-role result in the
         messages yet): stream ONLY ``tool_calls`` deltas — ``ls``
         with ``{"path": "."}`` (synthetic id ``call_0``),
         ``finish_reason: "tool_calls"``, no content — the incident's
         misuse, deterministic;
       * request 2 (a ``tool``-role result present that is NOT a
-        catalog listing — i.e. the teaching refusal): a ``tool_calls``
+        listing with file lines — i.e. the teaching refusal): a
-        delta — ``ls`` with no arguments (id ``call_1``) — the
+        ``tool_calls`` delta — ``ls`` with no arguments (id ``call_1``)
-        correction;
+        — the correction;
-      * request 3 (a ``tool``-role result whose first line matches the
+      * request 3 (the top-level source listing in the messages —
-        ``^\\d+ documents:`` catalog header): a deterministic content
+        file lines still absent): the drill — a ``tool_calls`` delta
-        answer — ``These are the indexed documents: <first catalog
+        — ``ls`` scoped to the FIRST source of the listing
-        line>`` (the ``source: X | path: Y | title: Z`` line, parsed
+        (id ``call_2``);
-        with the ``_CATALOG_LINE_RE`` machinery), ``finish_reason:
+      * request 4 (a ``tool``-result with a ``source: X | path: Y |
-        "stop"`` — the loop ended in ONE correction, not at the round
+        title: Z`` file line in the messages — the folder listing):
+        a deterministic content answer — ``These are the indexed
+        documents: <first file line>`` (the line, parsed with the
+        ``_CATALOG_LINE_RE`` machinery), ``finish_reason: "stop"`` —
+        the loop ended in ONE correction + ONE drill, not at the round
         cap.
     Checked BEFORE the plain ``TOOLS_TRIGGER`` flow (the trigger
     phrases are disjoint substrings — the phase-71 ordering
     convention); no existing E2E question or fixture file contains the
     phrase, so every other suite is unaffected.
+  - user message containing ``drill down the tree`` (``DRILL_TRIGGER``,
+    phase 94 task 04 — the drill-down ``ls``'s dedicated story suite
+    ``tests/e2e/test_ls_tree_drilldown.py``) **and** the system prompt
+    carries the ``<tools>`` section -> the deterministic SCRIPTED
+    DRILL-DOWN flow: the question carries its own tool call after the
+    colon — ``drill down the tree: ls [target]`` (no target = the top
+    level; ``target`` = a source name or ``source/folder`` path) or
+    ``drill down the tree: read source/path`` — parsed by
+    ``_DRILL_CALL_RE`` from the RAW user message (the target keeps its
+    case), then discriminated statelessly from the tool results
+    (streaming only):
+      * request 1 (``tools`` offered, no ``tool``-role result in the
+        messages yet): the SCRIPTED call — ``ls`` with no arguments
+        for the top level, ``ls``/``read`` with the parsed target
+        otherwise (synthetic id ``call_0``);
+      * the last tool result is the NOT-A-FOLDER teaching refusal
+        (it carries ``"is not a folder"`` — the phase-94 task-03
+        teaching line, the refusal being VISIBLE to the model is what
+        fires this branch): the scripted one-round recovery — ``ls``
+        the target's SOURCE segment (id ``call_1``);
+      * the last tool result is a READ result (``"Document
+        <source/path>:…``): the deterministic echo answer ``Read
+        <source/path>. <first 80 chars of the read document's
+        content>`` (the phase-37 single-read shape — the grounded-
+        turn citation contract);
+      * the last tool result is the agent's ALREADY_IN_CONTEXT dedupe
+        refusal (the read target is already a top-2 retrieval
+        document — with the drill fixture that is DETERMINISTIC:
+        the read question names the file's path, so the file
+        self-matches the hybrid gate and its FULL text is in the
+        ``<documents>`` prompt): the model answers FROM THE PROMPT —
+        the deterministic answer ``Already in context: Read
+        <source/path>. <first 80 chars of the target document's text
+        as it appears in the ``<documents>`` block>`` (same citation
+        shape as the read-result branch — the document text reached
+        the model either way, and the answer proves it);
+      * any other last result (a top-level or folder LISTING landed):
+        the deterministic ECHO answer ``Here's the level I listed:\n
+        <the listing, verbatim>`` — the mock echoes what it received
+        (the house scripted-turn way of asserting on tool results):
+        the suite asserts on the exact tree level — the ``— N
+        documents`` lines, the stored folder summaries, the
+        ``source: X | path: Y | title: Z`` file lines, and the 50-line
+        cap + ``…and N more documents…`` note — through the rendered
+        answer, the only E2E lens on the LLM's context.
+    Checked BEFORE the plain ``TOOLS_TRIGGER`` flow (disjoint trigger
+    phrases — the phase-71/72 ordering convention; the trigger needs
+    the ``<tools>`` section, so deflected turns never hit it); no
+    existing E2E question or fixture file contains the phrase, so
+    every other suite is unaffected.
   - user message containing ``what are the correct llama.cpp
     arguments`` (``GREP_TEACH_TRIGGER``, the 2026-09-05 incident —
     the harness prior is that grep takes a REGEX; this app's grep is a
@@ -302,7 +378,8 @@ from typing import Any
 from fastapi import FastAPI
 from fastapi.responses import JSONResponse, StreamingResponse
 
-from app.rag.agent import CORRECTION_INSTRUCTION  # phase 71: the harness constant
+from app.rag.agent import ALREADY_IN_CONTEXT, CORRECTION_INSTRUCTION
+from app.rag.folder_summaries import FOLDER_HEADER_PREFIX  # phase 94: the mock's key
 
 app = FastAPI()
 
@@ -588,9 +665,92 @@ GREP_TEACH_PLAIN = "qwen3.8"
 #: plain step keys on it (a plain no-match line carries it not).
 GREP_TEACH_MARKER = "grep matches a plain substring"
 
-#: The agent's ``ls`` listing header (app.rag.agent ``_execute_tool``):
+# ---------------------------------------------------------------------------
-#: ``"N documents:"`` — the first line of every catalog tool result.
+# Phase 94 (task 04, the drill-down ls's dedicated story suite):
-_CATALOG_HEADER_RE = re.compile(r"^\d+ documents:")
+# the deterministic SCRIPTED drill-down turns — see the module docstring
+# ---------------------------------------------------------------------------
+
+#: A user message containing this substring (case-insensitive) —
+#: combined with the ``<tools>`` section in the system prompt — drives
+#: the scripted DRILL-DOWN flow: the question carries its own tool call
+#: after the colon (``drill down the tree: ls [target]`` / ``drill
+#: down the tree: read source/path`` — the suite's scripted turns,
+#: ``tests/e2e/test_ls_tree_drilldown.py``). Checked BEFORE the plain
+#: ``TOOLS_TRIGGER`` flow (disjoint trigger phrases — the phase-71/72
+#: ordering convention); verified: no existing E2E question or fixture
+#: file contains the phrase, so every other suite is unaffected.
+DRILL_TRIGGER = "drill down the tree"
+
+#: The scripted call in the drill-down question (case-insensitive — the
+#: suite's questions capitalize the trigger's first letter): the verb
+#: (``ls`` / ``read``) plus the optional target — a source name or
+#: ``source/folder`` path (``ls``) or a combined ``source/path``
+#: (``read``), parsed from the RAW user message so the target keeps its
+#: case. The target is a ``[a-z0-9_./-]`` run (case-insensitively), so
+#: the suite's `` — `` flavor separator (em dash) can never bleed into
+#: it; no run = the top-level ``ls`` (no ``path`` argument).
+_DRILL_CALL_RE = re.compile(
+    r"drill down the tree:\s*(?P<verb>ls|read)(?:\s+(?P<arg>[a-z0-9_./-]+))?",
+    re.I,
+)
+
+#: The agent's NOT-A-FOLDER teaching refusal marker (app.rag.agent
+#: ``NOT_A_FOLDER`` — ``'{arg}' is not a folder — {parent} has:
+#: {subfolders}``): the drill-down flow's scripted recovery keys on it
+#: in the LAST tool result (the refusal being visible to the model is
+#: exactly what triggers the one-round recovery — the phase-72
+#: self-correction contract carrying the tree's teaching line).
+_NOT_A_FOLDER_MARKER = "is not a folder"
+
+#: The stable substring of the harness-owned dedupe refusal the
+#: drill-down flow's ``ctx_answer`` branch keys on (a read target that
+#: is already a top-2 retrieval document — the mock then answers from
+#: the document's text in the ``<documents>`` prompt block, exactly
+#: what the refusal instructs). Keyed on a substring (not the whole
+#: constant) so a re-wrap of the constant cannot silently re-route the
+#: mock; the module-level assert below fails loudly if the substring
+#: ever leaves the constant (the mock must never drift from
+#: ``app.rag.agent.ALREADY_IN_CONTEXT``).
+_ALREADY_IN_CONTEXT_MARKER = "Already in your context"
+assert _ALREADY_IN_CONTEXT_MARKER in ALREADY_IN_CONTEXT, (
+    "mock drift: the dedupe marker left ALREADY_IN_CONTEXT"
+)
+
+#: One ``<document>`` block of the HIGH prompt's ``<documents>``
+#: section (``app.rag.prompts.build_high_prompt``): the block is the
+#: document identity (``source``/``path``/``title`` attributes) plus
+#: the document's FULL text (never truncated on the retrieval path,
+#: owner-locked A7) between the tags.
+_DOCUMENT_BLOCK_RE = re.compile(
+    r'<document source="(?P<source>[^"]+)" path="(?P<path>[^"]+)" '
+    r'title="[^"]*">\n(?P<content>.*?)\n</document>',
+    re.S,
+)
+
+
+def _document_block(system: str, source: str, path: str) -> str | None:
+    """The stored text of one ``<document>`` block (or ``None``).
+
+    The drill-down flow's ``ctx_answer`` branch: when the agent's read
+    of a top-2 retrieval document gets the ALREADY_IN_CONTEXT dedupe,
+    the document's full text is in the ``<documents>`` prompt — the
+    mock (the model) extracts it by the block's identity attributes
+    and quotes it, answering from the prompt as the refusal instructs.
+    """
+    for block in _DOCUMENT_BLOCK_RE.finditer(system):
+        if block.group("source") == source and block.group("path") == path:
+            return block.group("content")
+    return None
+
+#: The agent's drill-down ``ls`` result shapes (app.rag.agent
+#: ``render_ls_top`` / ``render_folder_listing``, phase 94): the
+#: top-level header ``"N sources:"`` and the per-source block line
+#: ``"<source> — N documents"`` (summary lines are indented — they
+#: never match); the folder-level header ``"<identity> — N documents,
+#: M folders:"`` (identity = the source name or ``source/folder``).
+_SOURCE_HEADER_RE = re.compile(r"^\d+ sources:$")
+_SOURCE_LINE_RE = re.compile(r"^(?P<source>.+?) — (?P<n>\d+) documents$")
+_FOLDER_HEADER_RE = re.compile(r"^(?P<identity>.+?) — \d+ documents, \d+ folders:$")
 
 #: One DEAD app-level chat attempt costs exactly this many HTTP POSTs
 #: while the endpoint stays down: the openai SDK's default policy
@@ -713,26 +873,60 @@ def _tool_results(body: dict[str, Any]) -> list[str]:
     ]
 
 
-def _first_catalog_line(body: dict[str, Any]) -> str | None:
+def _first_file_line(body: dict[str, Any]) -> str | None:
-    """The first catalog line of a catalog listing in the messages.
+    """The first file line (``source: X | path: Y | title: Z``) across
+    the ``tool``-role results in the messages, in message order (read
+    results — full documents, not listings — skipped; the ``_CATALOG_-
+    LINE_RE`` machinery).
 
-    A catalog listing is a ``tool``-role result whose FIRST line is the
+    Phase 94: the drill-down ``ls`` carries file lines only at folder
-    agent's ``"N documents:"`` header (``_CATALOG_HEADER_RE``); its
+    levels — the top-level source listing and the teaching refusals
-    first ``source: X | path: Y | title: Z`` line (the
+    have none, so ``None`` here means "no folder level reached yet".
-    ``_CATALOG_LINE_RE`` machinery) is returned. ``None`` when no
-    catalog listing is in the messages — e.g. while only the teaching
-    refusal is there (the phase-72 LS-TEACH flow's request-2 state).
-    An empty listing (``"0 documents:"`` with no lines) returns
-    ``""`` — the listing is present, it is just empty.
     """
     for content in _tool_results(body):
-        lines = content.splitlines()
+        if content.startswith(_READ_RESULT_PREFIX):
-        if not lines or not _CATALOG_HEADER_RE.match(lines[0]):
             continue
-        for line in lines[1:]:
+        for line in content.splitlines():
             if _CATALOG_LINE_RE.match(line):
                 return line
-        return ""
+    return None
+
+
+def _drill_target(body: dict[str, Any]) -> str | None:
+    """The next source to drill into (phase 94, the drill step).
+
+    The drill-down ``ls`` top level lists SOURCES only (no file lines),
+    so a deterministic flow that needs a file line must drill one level:
+    ``ls`` scoped to a source. The target is the FIRST source of the
+    top-level listing (registry order — the listing's own order) that
+    does not yet have a folder-level listing in the messages (a folder
+    header whose identity is the source or ``source/…``); ``None`` when
+    no top-level listing is in the messages yet (nothing to drill from)
+    or every listed source has been drilled (an empty KB — the flow
+    degenerates to the old re-list loop, settling at the round cap
+    exactly like the phase-70 empty-catalog case).
+    """
+    sources: list[str] = []
+    drilled: set[str] = set()
+    for content in _tool_results(body):
+        lines = content.splitlines()
+        if not lines:
+            continue
+        if _SOURCE_HEADER_RE.match(lines[0]):
+            for line in lines[1:]:
+                match = _SOURCE_LINE_RE.match(line)
+                if match:
+                    sources.append(match.group("source"))
+        else:
+            folder = _FOLDER_HEADER_RE.match(lines[0])
+            if folder:
+                drilled.add(folder.group("identity"))
+    for source in sources:
+        if not any(
+            identity == source or identity.startswith(source + "/")
+            for identity in drilled
+        ):
+            return source
     return None
 
 
@@ -853,11 +1047,14 @@ def _tool_flow(body: dict[str, Any]) -> tuple[str, ...] | None:
     ``TOOLS_TRIGGER`` and ``MULTI_READ_TRIGGER``), classified by the
     count of ``tool``-role read results:
 
-    * 0 read results: ``("list", "", "")`` (no catalog yet) or
+    * 0 read results: ``("list", "", "")`` (no listing yet),
-      ``("read", source, path, "call_1")`` on the FIRST catalog doc.
+      ``("drill", source, "call_1")`` when the top-level source
-    * 1 read result: ``("read", source, path, "call_2")`` on the SECOND
+      listing is in the messages but no file line yet (phase 94: the
-      catalog doc — the first listing line whose ``source/path``
+      drill — the top level carries sources only), or
-      differs from the one already read. A one-document catalog
+      ``("read", source, path, "call_2")`` on the FIRST file-line doc.
+    * 1 read result: ``("read", source, path, "call_3")`` on the SECOND
+      file-line doc — the first listing line whose ``source/path``
+      differs from the one already read. A one-file listing
       degenerates to the single-read ``("answer", ...)`` shape (nothing
       second to read).
     * 2 read results: ``("multi_answer", "", text)`` — the forced
@@ -880,30 +1077,37 @@ def _tool_flow(body: dict[str, Any]) -> tuple[str, ...] | None:
             if not body.get("tools"):
                 return None
             docs = _catalog_docs(body)
-            if not docs:
+            if docs:
-                return ("list", "", "")
+                return ("read", docs[0][0], docs[0][1], "call_2")
-            return ("read", docs[0][0], docs[0][1], "call_1")
+            drill = _drill_target(body)
+            if drill is not None:
+                return ("drill", drill, "call_1")
+            return ("list", "", "")
         if len(reads) == 1:
             skip = reads[0][0]
             second = next(
                 (d for d in _catalog_docs(body) if f"{d[0]}/{d[1]}" != skip), None
             )
             if second is None:
-                # One-document catalog: nothing second to read — the
+                # One-file listing: nothing second to read — the
                 # single-read answer shape (deterministic degenerate).
                 return ("answer", reads[0][0], reads[0][1])
-            return ("read", second[0], second[1], "call_2")
+            return ("read", second[0], second[1], "call_3")
         (sp1, c1), (sp2, _c2) = reads[0], reads[1]
         answer = f"Read {sp1}. {c1[:80]} I read {sp1} and {sp2}."
         return ("multi_answer", "", answer)
-    # Phase-37 single-read flow — byte-identical to the original.
+    # Phase-37 single-read flow (phase 94: the drill step between the
+    # top-level listing and the first file line).
     if reads:
         return ("answer", reads[0][0], reads[0][1])
     if not body.get("tools"):
         return None
     docs = _catalog_docs(body)
     if docs:
-        return ("read", docs[0][0], docs[0][1], "call_1")
+        return ("read", docs[0][0], docs[0][1], "call_2")
+    drill = _drill_target(body)
+    if drill is not None:
+        return ("drill", drill, "call_1")
     return ("list", "", "")
 
 
@@ -915,13 +1119,17 @@ def _ls_teach_flow(body: dict[str, Any]) -> tuple[str, ...] | None:
       with ``{"path": "."}`` (id ``call_0``), ``finish_reason:
       "tool_calls"``, no content.
     * ``("correct",)`` — a ``tool``-role result is in the messages and
-      it is NOT a catalog listing (the teaching refusal): the
+      no file line exists yet (the teaching refusal): the correction —
-      correction — ``ls`` with no arguments (id ``call_1``).
+      ``ls`` with no arguments (id ``call_1``).
-    * ``("answer", line)`` — a ``tool``-role result whose first line
+    * ``("drill", source, "call_2")`` — the top-level source listing
-      is the ``"N documents:"`` catalog header: the deterministic
+      is in the messages (the correction ran) but no file line yet
+      (phase 94: the top level carries sources only): the drill —
+      ``ls`` scoped to the first source of the listing.
+    * ``("answer", line)`` — a ``source: X | path: Y | title: Z`` file
+      line is in the messages (the folder listing): the deterministic
       content answer ``These are the indexed documents: <line>`` (the
-      first catalog line), ``finish_reason: "stop"`` — the loop
+      first file line), ``finish_reason: "stop"`` — the loop settled
-      settled in ONE correction, not at the round cap.
+      in ONE correction + ONE drill, not at the round cap.
     * ``None`` — not the flow: the trigger is absent, the ``<tools>``
       section is missing (deflected turns never carry it), or
       ``tools`` are not offered and no tool results are in the
@@ -931,9 +1139,12 @@ def _ls_teach_flow(body: dict[str, Any]) -> tuple[str, ...] | None:
         return None
     if "<tools>" not in _system(body):
         return None
-    line = _first_catalog_line(body)
+    line = _first_file_line(body)
     if line is not None:
         return ("answer", line)
+    drill = _drill_target(body)
+    if drill is not None:
+        return ("drill", drill, "call_2")
     if _tool_results(body):
         return ("correct",)
     if not body.get("tools"):
@@ -996,6 +1207,92 @@ def _grep_teach_flow(body: dict[str, Any]) -> tuple[str, ...] | None:
     return ("nomatch",)
 
 
+def _drill_flow(body: dict[str, Any]) -> tuple[str, ...] | None:
+    """Classify a phase-94 scripted drill-down request (see the module
+    docstring). The question carries the scripted call
+    (``drill down the tree: ls [target]`` / ``drill down the tree: read
+    source/path``); the step is then discriminated statelessly from the
+    tool results, like the other marker flows:
+
+    * ``("call", verb, target, "call_0")`` — ``tools`` are offered and
+      no ``tool``-role result is in the messages yet: the scripted call
+      (``ls`` with NO path for the top level — empty target —, ``ls``
+      with the target for source/folder levels, ``read`` with the
+      combined ``source/path``).
+    * ``("recover", source)`` — the LAST tool result is the NOT-A-FOLDER
+      teaching refusal (it carries :data:`_NOT_A_FOLDER_MARKER`): the
+      scripted one-round recovery — ``ls`` the target's SOURCE segment
+      (the refusal listing the parent's subfolders is what lets the
+      model — and this mock — self-correct in the next round, the
+      phase-72 contract).
+    * ``("read_answer", combined, quote)`` — the LAST tool result is a
+      read result (``"Document <source/path>:\n<content>"``): the
+      deterministic echo answer ``Read <source/path>. <first 80 chars>
+      `` (the phase-37 single-read shape — the grounded-turn citation
+      contract the suite asserts).
+    * ``("ctx_answer", target, quote)`` — the scripted call was a
+      ``read`` and the LAST tool result is the ALREADY_IN_CONTEXT
+      dedupe refusal (the target is already a top-2 retrieval document
+      — deterministic for the drill fixture: the read question names
+      the file's path, so the file self-matches the hybrid gate): the
+      model answers FROM THE PROMPT — ``Already in context: Read
+      <target>. <first 80 chars of the target document's text in the
+      ``<documents>`` block>`` (the same citation shape as the
+      read-result branch — the document text reached the model either
+      way). Falls through to the echo when the target is not a
+      ``<document>`` block (the premise broke — the suite fails
+      loudly on the answer).
+    * ``("echo", listing)`` — a listing landed (top-level or folder —
+      any other last result): the deterministic ECHO — the answer
+      carries the listing VERBATIM (``Here's the level I listed:\n
+      <listing>``), so the suite asserts on the exact tree level the
+      model saw (source ``— N documents`` lines + stored summaries,
+      subfolder lines, the ``source: X | path: Y | title: Z`` file
+      lines, the 50-line cap + note) through the rendered answer — the
+      house scripted-turn way of asserting on tool results (the mock is
+      the only E2E lens on the LLM's context).
+    * ``None`` — not the flow: the trigger is absent, the ``<tools>``
+      section is missing (deflected turns never carry it), the scripted
+      call is unparseable, or ``tools`` are not offered and no tool
+      results are in the messages yet (e.g. ``agent_max_rounds=0``).
+    """
+    user = _user(body)
+    if DRILL_TRIGGER not in user.lower():
+        return None
+    if "<tools>" not in _system(body):
+        return None
+    match = _DRILL_CALL_RE.search(user)
+    if match is None:
+        return None
+    verb = match.group("verb")
+    target = match.group("arg") or ""
+    results = _tool_results(body)
+    if not results:
+        if not body.get("tools"):
+            return None
+        return ("call", verb, target, "call_0")
+    last = results[-1]
+    if last.startswith(_READ_RESULT_PREFIX):
+        head, _, content = last.partition("\n")
+        # The read result is ``"Document <source/path>:\n<content>"`` —
+        # the head carries the server's appended ``:`` (removed here;
+        # a document path never legitimately ends with one).
+        combined = head[len(_READ_RESULT_PREFIX):].strip().removesuffix(":")
+        return ("read_answer", combined, content[:80])
+    if _ALREADY_IN_CONTEXT_MARKER in last and verb == "read" and "/" in target:
+        # The dedupe fired: the read target is already a top-2
+        # retrieval document, so its FULL text is in the
+        # ``<documents>`` prompt — answer from the prompt (the
+        # refusal's instruction), quoting the block's text.
+        src, _, p = target.partition("/")
+        content = _document_block(_system(body), src, p)
+        if content is not None:
+            return ("ctx_answer", target, content[:80])
+    if _NOT_A_FOLDER_MARKER in last:
+        return ("recover", target.split("/")[0])
+    return ("echo", last)
+
+
 def long_answer() -> str:
     """~900-word deterministic walkthrough (phase 11): numbered steps plus
     a unique final line that must survive the stream untruncated."""
@@ -1103,6 +1400,28 @@ def compose_answer(body: dict[str, Any]) -> str:
     user = _user(body)
     if LONG_ANSWER_TRIGGER in user.lower():
         answer = long_answer()
+    elif "FOLDER_SUMMARY_MODE" in system:
+        # Folder summary (phase 94, TODO.md L4): the ``lite`` stand-in
+        # returns the deterministic one-liner
+        # ``Fixture folder summary for <folder>.`` — <folder> is the
+        # user message's ``Folder: …`` header line (the generator puts
+        # the canonical source/folder identity there, imported as
+        # ``FOLDER_HEADER_PREFIX`` so the mock can never drift from it).
+        # The stored row therefore always names its folder — the drill-
+        # down E2E (``test_ls_tree_drilldown.py``) asserts on it.
+        # Checked BEFORE the ``SUMMARY_MODE`` branch: the folder marker
+        # CONTAINS the summary marker as a substring (``FOLDER_`` +
+        # ``SUMMARY_MODE``), so the summary branch would otherwise
+        # shadow every folder-summary call. Checked BEFORE the
+        # DEFLECT_MODE branch, like the other lite-mode markers (a
+        # deflection prompt never carries one).
+        header = user.splitlines()[0] if user else ""
+        folder = (
+            header.removeprefix(FOLDER_HEADER_PREFIX).strip()
+            if header.startswith(FOLDER_HEADER_PREFIX)
+            else "(unnamed folder)"
+        )
+        answer = f"Fixture folder summary for {folder}."
     elif "SUMMARY_MODE" in system:
         # Document summaries (phase 30): the ``lite`` stand-in returns a
         # deterministic digest — the first 24 tokens of the user message
@@ -1594,9 +1913,16 @@ def chat_completions(body: dict[str, Any]) -> Any:
                 # The incident's misuse, deterministic: ls(path='.').
                 stream = _tool_call_stream("ls", {"path": "."}, "call_0")
             elif ls_teach[0] == "correct":
-                # The one-round correction: the no-arg full listing.
+                # The one-round correction: the no-arg top-level
+                # listing (phase 94: sources only — the drill follows).
                 stream = _tool_call_stream("ls", {}, "call_1")
-            else:  # "answer" — quote the first catalog line
+            elif ls_teach[0] == "drill":
+                # Phase 94: the top level lists sources only — drill
+                # one level into the first source for the file lines.
+                stream = _tool_call_stream(
+                    "ls", {"path": ls_teach[1]}, ls_teach[2]
+                )
+            else:  # "answer" — quote the first file line
                 answer = _apply_max_tokens(
                     f"These are the indexed documents: {ls_teach[1]}",
                     body.get("max_tokens"),
@@ -1607,10 +1933,67 @@ def chat_completions(body: dict[str, Any]) -> Any:
                 media_type="text/event-stream",
                 headers={"Cache-Control": "no-cache", "X-Accel-Buffering": "no"},
             )
+        # Phase 94 (task 04): the deterministic SCRIPTED drill-down
+        # turns (sources → folders → files → the grounded read; the
+        # 50-line cap; the NOT-A-FOLDER teaching + scripted recovery) —
+        # checked BEFORE the plain TOOLS_TRIGGER flow (disjoint trigger
+        # phrases — the phase-71/72 ordering convention; the trigger
+        # needs the ``<tools>`` section, so deflected turns never hit
+        # it).
+        drill = _drill_flow(body)
+        if drill is not None:
+            if drill[0] == "call":
+                # The scripted call: ls with no path at the top level
+                # (empty target), ls/read with the parsed target.
+                stream = _tool_call_stream(
+                    drill[1], {"path": drill[2]} if drill[2] else {}, drill[3]
+                )
+            elif drill[0] == "recover":
+                # The scripted one-round recovery after the NOT-A-FOLDER
+                # teaching: ls the target's source (the parent level).
+                stream = _tool_call_stream("ls", {"path": drill[1]}, "call_1")
+            elif drill[0] == "read_answer":
+                # Quote the read document (first 80 chars) — the
+                # phase-37 single-read shape.
+                stream = _sse_stream(
+                    _apply_max_tokens(
+                        f"Read {drill[1]}. {drill[2]}", body.get("max_tokens")
+                    ),
+                    0.0,
+                )
+            elif drill[0] == "ctx_answer":
+                # The dedupe fired: the target's full text is in the
+                # <documents> prompt — answer from it (same citation
+                # shape, prefixed so the suite pins the dedupe path).
+                stream = _sse_stream(
+                    _apply_max_tokens(
+                        f"Already in context: Read {drill[1]}. {drill[2]}",
+                        body.get("max_tokens"),
+                    ),
+                    0.0,
+                )
+            else:  # "echo" — the listing verbatim (the suite's lens)
+                stream = _sse_stream(
+                    _apply_max_tokens(
+                        f"Here's the level I listed:\n{drill[1]}",
+                        body.get("max_tokens"),
+                    ),
+                    0.0,
+                )
+            return StreamingResponse(
+                stream,
+                media_type="text/event-stream",
+                headers={"Cache-Control": "no-cache", "X-Accel-Buffering": "no"},
+            )
         flow = _tool_flow(body)
         if flow is not None:
             if flow[0] == "list":
                 stream = _tool_call_stream("ls", {}, "call_0")
+            elif flow[0] == "drill":
+                # Phase 94: the drill step — ls scoped to the first
+                # source of the top-level listing (flow[1], flow[2] is
+                # the synthetic call id).
+                stream = _tool_call_stream("ls", {"path": flow[1]}, flow[2])
             elif flow[0] == "read":
                 # flow[3] is the synthetic call id — "call_1" for the
                 # single-read flow and the multi-read first read,

tests/e2e/test_agent_document_tools.py

@@ -11,15 +11,22 @@ deterministic marker flow in ``tests/e2e/mock_llm.py`` (user message
 contains ``use your tools`` **and** the system prompt carries the
 ``<tools>`` section of the HIGH prompt; phase 70: the flow emits the
 harness-aligned names — ``ls`` / ``read`` with the combined
-``source/path`` identity):
+``source/path`` identity; phase 94: the drill-down ``ls`` — the top
+level lists sources only, so the flow drills one level into the first
+source before the first file line exists):
 
 1. request 1 (``tools`` offered, no tool results yet) → streams ONLY
    ``tool_calls`` deltas calling ``ls`` (id ``call_0``, no arguments,
    ``finish_reason: "tool_calls"``);
-2. request 2 (a ``tool``-role catalog result in the messages) → streams a
+2. request 2 (the top-level source listing in the messages — no file
-   ``tool_calls`` delta calling ``read`` on the JOINED combined
+   lines yet) → a ``tool_calls`` delta — ``ls`` scoped to the FIRST
-   ``source/path`` of the FIRST catalog line (id ``call_1``);
+   source of the listing (id ``call_1``) — the drill step (the seed
-3. request 3 (a ``tool``-role read result in the messages) → the content
+   registers ``Deployments`` first, so the drill — and therefore the
+   read — lands on the JSON file);
+3. request 3 (a ``tool``-role folder listing with file lines) → streams
+   a ``tool_calls`` delta calling ``read`` on the JOINED combined
+   ``source/path`` of the FIRST file line (id ``call_2``);
+4. request 4 (a ``tool``-role read result in the messages) → the content
    answer ``Read <source/path>. <first 80 chars of the read document's
    content>`` — so the suite can assert the read document reached the
    model and landed in the answer.
@@ -72,7 +79,7 @@ from sqlalchemy import select, text
 from sqlalchemy.orm import Session
 
 from app.db import SessionLocal
-from app.models import Chunk, Document, QueryLog
+from app.models import Chunk, Document, GitSource, QueryLog
 from e2e.auth_helpers import login
 from tests.e2e.mock_llm import embed_text
 
@@ -148,7 +155,22 @@ READ_CHIP_HREF = f"/document.html?source={READ_SOURCE}&path={READ_PATH}&back=%2F
 
 
 def _seed(db: Session) -> None:
-    """The two-document pair from the TODO (see the module docstring)."""
+    """The two-document pair from the TODO (see the module docstring).
+
+    Phase 94: the drill-down ``ls`` top level reads the registry — the
+    seed registers BOTH sources (TRUNCATEd in ``_reset_db``),
+    ``Deployments`` FIRST: registry order is ``(added_at, id)``, so the
+    mock's drill (first source of the listing) lands on the JSON file
+    deterministically — independent of the operator's
+    ``BOR_GIT_SOURCES`` (a non-empty table ignores the env fallback).
+    """
+    # COMMIT between the inserts (not flush): ``added_at`` is
+    # ``server_default now()`` — the transaction timestamp — and the
+    # tie-break is the random uuid ``id``, so one-transaction rows order
+    # nondeterministically.
+    db.add(GitSource(url=READ_SOURCE, kind="local"))
+    db.commit()
+    db.add(GitSource(url=SEED_SOURCE, kind="local"))
     md = Document(
         source=SEED_SOURCE,
         path=SEED_PATH,
@@ -195,7 +217,10 @@ def _reset_db(seed: Callable[[Session], None] | None = None) -> None:
     """
     with SessionLocal() as db:
         db.execute(
-            text("TRUNCATE chunks, documents, query_log, steering_notes, kb_overview")
+            text(
+                "TRUNCATE chunks, documents, query_log, steering_notes, "
+                "kb_overview, git_sources"
+            )
         )
         db.commit()
         if seed is not None:
@@ -389,12 +414,14 @@ def test_marker_question_lists_reads_and_quotes(
     assert i_list is not None and i_read is not None, statuses
     assert i_list < i_read, statuses
 
-    # Wire level: exactly two `tool` frames — ``ls`` then ``read`` (the
+    # Wire level: exactly three `tool` frames — ``ls`` (the top level),
-    # combined source/path as the model passed it) — and both ahead of
+    # the drill ``ls`` scoped to the first source (phase 94), then
-    # the first `delta` frame.
+    # ``read`` (the combined source/path as the model passed it) — and
+    # all three ahead of the first `delta` frame.
     frames = _frames(page)
     assert _tool_frames(frames) == [
         {"type": "tool", "name": "ls", "argument": None},
+        {"type": "tool", "name": "ls", "argument": READ_SOURCE},
         {"type": "tool", "name": "read", "argument": READ_SP},
     ]
     first_delta = next(i for i, f in enumerate(frames) if f.get("type") == "delta")
@@ -408,12 +435,15 @@ def test_marker_question_lists_reads_and_quotes(
         (READ_SOURCE, READ_PATH),
     ]
 
-    # Both tool lines, in order, above the answer.
+    # All three tool lines, in order, above the answer (phase 94: the
+    # drill line is "Listing documents in <source>").
     lines = page.locator(".msg.brain .tool-call")
-    expect(lines).to_have_count(2)
+    expect(lines).to_have_count(3)
     expect(lines.nth(0)).to_contain_text("Listing documents")
-    expect(lines.nth(1)).to_contain_text("Reading ")
+    expect(lines.nth(1)).to_contain_text("Listing documents in")
-    expect(lines.nth(1)).to_contain_text(READ_SP)
+    expect(lines.nth(1)).to_contain_text(READ_SOURCE)
+    expect(lines.nth(2)).to_contain_text("Reading ")
+    expect(lines.nth(2)).to_contain_text(READ_SP)
 
     # The final answer quotes the read document (the mock's deterministic
     # quote: "Read <source/path>. <first 80 chars of its content>").
@@ -451,18 +481,20 @@ def test_tool_lines_re_render_after_reload(
 
     _submit(page, MARKER_QUESTION)
     _wait_settled(page)
-    expect(page.locator(".msg.brain .tool-call")).to_have_count(2)
+    expect(page.locator(".msg.brain .tool-call")).to_have_count(3)
 
     page.reload()
     expect(page.locator("#empty-state")).to_be_hidden()
 
-    # The persisted record re-renders BOTH tool lines, in saved order,
+    # The persisted record re-renders ALL THREE tool lines, in saved
-    # through the same append helper as the live frames.
+    # order, through the same append helper as the live frames.
     restored = page.locator(".msg.brain .tool-call")
-    expect(restored).to_have_count(2)
+    expect(restored).to_have_count(3)
     expect(restored.nth(0)).to_contain_text("Listing documents")
-    expect(restored.nth(1)).to_contain_text("Reading ")
+    expect(restored.nth(1)).to_contain_text("Listing documents in")
-    expect(restored.nth(1)).to_contain_text(READ_SP)
+    expect(restored.nth(1)).to_contain_text(READ_SOURCE)
+    expect(restored.nth(2)).to_contain_text("Reading ")
+    expect(restored.nth(2)).to_contain_text(READ_SP)
 
     # Answer + the read-document chip are intact (phase-14 restore path).
     bubble = page.locator(".msg.brain .bubble").last

tests/e2e/test_agent_unlimited_tools.py

@@ -11,19 +11,26 @@ message contains BOTH ``use your tools`` (``TOOLS_TRIGGER``) and ``read
 two documents`` (``MULTI_READ_TRIGGER``) **and** the system prompt
 carries the ``<tools>`` section of the HIGH prompt; phase 70: the flow
 emits the harness-aligned names — ``ls``, then ``read`` on the JOINED
-combined ``source/path`` of each catalog line):
+combined ``source/path`` of each file line; phase 94: the drill-down
+``ls`` — the top level lists sources only, so the flow drills one
+level into the first source before the first file line exists):
 
 1. request 1 (``tools`` offered, no tool results yet) → streams ONLY
    ``tool_calls`` deltas calling ``ls`` (id ``call_0``);
-2. request 2 (the ``tool``-role catalog result) → ``read`` on the
+2. request 2 (the top-level source listing in the messages — no file
-   JOINED combined ``source/path`` of the FIRST catalog line
+   lines yet) → the drill: ``ls`` scoped to the FIRST source of the
-   (id ``call_1``);
+   listing (id ``call_1``); the seed registers ``Deployments`` first,
-3. request 3 (one ``tool``-role read result) → ``read`` on the JOINED
+   and both read documents live in it — so the drill's folder listing
-   combined ``source/path`` of the SECOND catalog line (id ``call_2``)
+   carries BOTH file lines;
-   — the pre-phase-45 per-tool budgets would have refused exactly this
+3. request 3 (a ``tool``-role folder listing with file lines) →
+   ``read`` on the JOINED combined ``source/path`` of the FIRST file
+   line (id ``call_2``);
+4. request 4 (one ``tool``-role read result) → ``read`` on the JOINED
+   combined ``source/path`` of the SECOND file line (id ``call_3``) —
+   the pre-phase-45 per-tool budgets would have refused exactly this
    second read (``No reading budget left — answer with what you
    have.``);
-4. request 4 (two read results) → the forced answer, byte-stable: the
+5. request 5 (two read results) → the forced answer, byte-stable: the
    single-read shape quoting the FIRST read result, plus the line
    ``I read <sp1> and <sp2>.`` naming both read paths in read order.
 
@@ -49,10 +56,11 @@ rejection, not the multi-read
 flow this story proves.
 
 Test → story mapping (Playwright Mapping Rule):
-1. ``test_multi_read_turn`` — the turn streams THREE ``tool`` frames /
+1. ``test_multi_read_turn`` — the turn streams FOUR ``tool`` frames /
-   ``.tool-call`` lines in order (one list — "is listing documents" —
+   ``.tool-call`` lines in order (the top-level list, the drill list —
-   and two reads — "is reading <source/path>" — the #send-status
+   phase 94 — "is listing documents", and two reads — "is reading
-   transition recorded deterministically via MutationObserver), then a
+   <source/path>" — the #send-status transition recorded
+   deterministically via MutationObserver), then a
    final non-deflected answer containing the mock's byte-stable
    ``I read <sp1> and <sp2>.`` line; the round cap (default 10) bounds
    the turn, no budget refusal anywhere.
@@ -84,7 +92,7 @@ from sqlalchemy import select, text
 from sqlalchemy.orm import Session
 
 from app.db import SessionLocal
-from app.models import Chunk, Document, QueryLog
+from app.models import Chunk, Document, GitSource, QueryLog
 from e2e.auth_helpers import login
 from tests.e2e.mock_llm import embed_text
 
@@ -209,7 +217,23 @@ def _doc(source: str, path: str, title: str, content: str) -> Document:
 
 
 def _seed(db: Session) -> None:
-    """The three-document KB from the module docstring."""
+    """The three-document KB from the module docstring.
+
+    Phase 94: the drill-down ``ls`` top level reads the registry —
+    register BOTH sources (TRUNCATEd in ``_reset_db``), ``Deployments``
+    FIRST (registry order is ``(added_at, id)``): the mock's drill
+    (first source of the listing) lands on the folder that carries
+    BOTH file lines. A non-empty table also ignores the operator's
+    ``BOR_GIT_SOURCES`` fallback — deterministic.
+    """
+    # COMMIT between the inserts (not flush): ``added_at`` is
+    # ``server_default now()`` — the transaction timestamp — and the
+    # tie-break is the RANDOM uuid ``id``, so two rows in one
+    # transaction order nondeterministically (the integration
+    # ``registry`` fixture's pattern).
+    db.add(GitSource(url=READ1_SOURCE, kind="local"))
+    db.commit()
+    db.add(GitSource(url=SEED_SOURCE, kind="local"))
     md = _doc(SEED_SOURCE, SEED_PATH, "AWS Route 53 Notes", ROUTE53_CONTENT)
     db.add(md)
     db.flush()
@@ -240,7 +264,10 @@ def _reset_db(seed: Callable[[Session], None] | None = None) -> None:
     """
     with SessionLocal() as db:
         db.execute(
-            text("TRUNCATE chunks, documents, query_log, steering_notes, kb_overview")
+            text(
+                "TRUNCATE chunks, documents, query_log, steering_notes, "
+                "kb_overview, git_sources"
+            )
         )
         db.commit()
         if seed is not None:
@@ -399,13 +426,16 @@ def test_multi_read_turn(
     _submit(page, MULTI_QUESTION)
     _wait_settled(page)
 
-    # Wire level: exactly THREE `tool` frames — ls, read #1, read #2
+    # Wire level: exactly FOUR `tool` frames — the top-level ls, the
-    # (each read's argument is the JOINED combined source/path), in
+    # drill ls scoped to the first source (phase 94), then read #1 and
-    # order — and all ahead of the first `delta` frame. This third
+    # read #2 (each read's argument is the JOINED combined
-    # frame is the one the pre-phase-45 read budget refused.
+    # source/path), in order — and all ahead of the first `delta`
+    # frame. The fourth frame is the one the pre-phase-45 read budget
+    # refused.
     frames = _frames(page)
     assert _tool_frames(frames) == [
         {"type": "tool", "name": "ls", "argument": None},
+        {"type": "tool", "name": "ls", "argument": READ1_SOURCE},
         {"type": "tool", "name": "read", "argument": READ1_SP},
         {"type": "tool", "name": "read", "argument": READ2_SP},
     ]
@@ -439,14 +469,17 @@ def test_multi_read_turn(
     ), statuses
     assert i_list < i_read1 < i_read2, statuses
 
-    # Three visible tool lines, in order, above the answer.
+    # Four visible tool lines, in order, above the answer (phase 94:
+    # the drill line is "Listing documents in <source>").
     lines = page.locator(".msg.brain .tool-call")
-    expect(lines).to_have_count(3)
+    expect(lines).to_have_count(4)
     expect(lines.nth(0)).to_contain_text("Listing documents")
-    expect(lines.nth(1)).to_contain_text("Reading ")
+    expect(lines.nth(1)).to_contain_text("Listing documents in")
-    expect(lines.nth(1)).to_contain_text(READ1_SP)
+    expect(lines.nth(1)).to_contain_text(READ1_SOURCE)
     expect(lines.nth(2)).to_contain_text("Reading ")
-    expect(lines.nth(2)).to_contain_text(READ2_SP)
+    expect(lines.nth(2)).to_contain_text(READ1_SP)
+    expect(lines.nth(3)).to_contain_text("Reading ")
+    expect(lines.nth(3)).to_contain_text(READ2_SP)
 
     # The final answer is non-deflected, quotes the FIRST read result,
     # and names BOTH read paths (the mock's byte-stable line).
@@ -563,19 +596,23 @@ def test_single_tool_flow_regression(
     _submit(page, SINGLE_QUESTION)
     _wait_settled(page)
 
-    # Exactly TWO tool frames — ls then ONE read of the first catalog
+    # Exactly THREE tool frames — the top-level ls, the drill ls
-    # line (the JOINED combined source/path) — no second read (the
+    # (phase 94), then ONE read of the first file line (the JOINED
-    # marker carries no multi-read trigger).
+    # combined source/path) — no second read (the marker carries no
+    # multi-read trigger).
     frames = _frames(page)
     assert _tool_frames(frames) == [
         {"type": "tool", "name": "ls", "argument": None},
+        {"type": "tool", "name": "ls", "argument": READ1_SOURCE},
         {"type": "tool", "name": "read", "argument": READ1_SP},
     ]
     lines = page.locator(".msg.brain .tool-call")
-    expect(lines).to_have_count(2)
+    expect(lines).to_have_count(3)
     expect(lines.nth(0)).to_contain_text("Listing documents")
-    expect(lines.nth(1)).to_contain_text("Reading ")
+    expect(lines.nth(1)).to_contain_text("Listing documents in")
-    expect(lines.nth(1)).to_contain_text(READ1_SP)
+    expect(lines.nth(1)).to_contain_text(READ1_SOURCE)
+    expect(lines.nth(2)).to_contain_text("Reading ")
+    expect(lines.nth(2)).to_contain_text(READ1_SP)
 
     # The single-read answer shape: quotes the read document; it does
     # NOT carry the multi-read both-named line (READ2 was never read).

tests/e2e/test_big_read_progress.py

@@ -19,27 +19,33 @@ phase-64 default 0.15 is far below the 5 s tool-line threshold):
 
 NOTE the prelude: the chat flow's QUESTION EMBEDDING also travels
 through the proxy (one 6 s sleep) before the agent loop starts, so
-the wall-clock timeline of one turn is:
+the wall-clock timeline of one turn is (phase 94: the drill-down
+``ls`` adds a drill step — the top level lists sources only, so the
+flow drills one level before the first file line exists):
 
 1. t≈12 s — the first SSE ``tool`` frame ("🔎 Listing documents"): the
    6 s embedding sleep + request 1's 6 s sleep (``tools`` offered, no
    tool results yet — streams ONLY the ``ls`` ``tool_calls`` delta,
    id ``call_0``) + the mock's ~0.2 s tool-call stream;
-2. t≈19 s — the second ``tool`` frame ("📄 Reading
+2. t≈19 s — the second ``tool`` frame ("🔎 Listing documents in
-   Deployments/example-record-file.json"): request 2's 6 s sleep (a
+   Deployments"): request 2's 6 s sleep (the top-level source listing
-   ``tool``-role catalog result → streams a ``read`` ``tool_calls``
+   in the messages — no file lines yet → streams the drill ``ls``
-   delta on the JOINED combined ``source/path`` of the FIRST catalog
+   scoped to the first source, id ``call_1``);
-   line, id ``call_1``);
+3. t≈25 s — the third ``tool`` frame ("📄 Reading
-3. t≈25 s — the content answer ``Read <source/path>. <first 80 chars
+   Deployments/example-record-file.json"): request 3's 6 s sleep (a
-   of the read document's content>``: request 3's 6 s sleep (a
+   ``tool``-role folder listing with file lines → streams a ``read``
+   ``tool_calls`` delta on the JOINED combined ``source/path`` of the
+   FIRST file line, id ``call_2``);
+4. t≈31 s — the content answer ``Read <source/path>. <first 80 chars
+   of the read document's content>``: request 4's 6 s sleep (a
    ``tool``-role read result) → the first answer ``delta``.
 
 So each post-tool-frame gap (≈6.3 s — the 6 s sleep + the short
 tool-call stream) is PAST the 5 s tool-line threshold
 (``TOOL_LINE_ELAPSED_AFTER_MS = 5_000``), and the 10 s pre-token
 typing hint (the existing ``startThinkingClock`` gate, ticking from
-t≈0) is visible throughout both post-tool gaps — everything before the
+t≈0) is visible throughout all post-tool gaps — everything before the
-answer's first delta (the whole turn runs ≈25 s + overhead, acceptable
+answer's first delta (the whole turn runs ≈31 s + overhead, acceptable
 for an isolated story suite). The four tests pin: (1) the latest tool
 line's ticking "(Ns)" suffix, (2) the typing indicator's visible "Ns"
 hint (+ the kept aria channel), (3) BOTH settling the instant the
@@ -55,15 +61,20 @@ task that writes the visible span) — so the two channels read
 polls until they align (the deterministic same-moment pin).
 
 **KB fixture** — byte-identical to the phase-37 suite
-(``tests/e2e/test_agent_document_tools.py``): ``Homelab/aws-route53.md``
+(``tests/e2e/test_agent_document_tools.py``), plus the phase-94
+registry rows: both sources are registered in ``git_sources``
+(``Deployments`` FIRST — registry order ``(added_at, id)``), so the
+mock's drill (first source of the top-level listing) lands on the
+folder that carries the file lines. ``Homelab/aws-route53.md``
 carries one chunk embedded with the mock's own bag-of-words vector —
 the marker question (phase 37's exact question, which carries the
 trigger phrase) cosines ≈0.69 against it, well past the E2E 0.30
 threshold, so the turn is grounded and the HIGH prompt carries the
 ``<tools>`` section; ``Deployments/example-record-file.json`` is
 indexed WITHOUT chunks, and its ``(source, path)`` sorts FIRST in the
-catalog (``Deployments`` < ``Homelab``) — exactly the line the mock's
+folder listing's file lines (``Deployments`` < ``Homelab``) — exactly
-second request reads, so the answer is byte-stable.
+the line the mock's read request targets, so the answer is
+byte-stable.
 
 Test → story mapping (Playwright Mapping Rule):
 1. ``test_tool_line_shows_ticking_elapsed``
@@ -92,7 +103,7 @@ from sqlalchemy.orm import Session
 
 from app.config import Settings as _Settings
 from app.db import SessionLocal
-from app.models import Chunk, Document
+from app.models import Chunk, Document, GitSource
 from e2e.auth_helpers import login
 from e2e.conftest import (
     ADMIN_PASSWORD,
@@ -211,8 +222,10 @@ SUFFIX_TIMEOUT_MS = 12_000
 #: the indicator is removed at the first delta (≈25 s): 20 s from the
 #: check start cannot flake.
 TYPING_HINT_TIMEOUT_MS = 20_000
-#: The answer settles at ≈19 s from submit; every settle wait here starts
+#: The answer settles at ≈31 s from submit (phase 94: the drill step
-#: ≥12 s in — 30 s keeps ≥2× headroom on the remaining window.
+#: adds a third tool round); every settle wait here starts ≈17 s in
+#: (after the first line's suffix) — 30 s keeps ≥2× headroom on the
+#: remaining window.
 SETTLE_TIMEOUT_MS = 30_000
 #: The restore is a synchronous boot re-render — 15 s is ample.
 RESTORE_TIMEOUT_MS = 15_000
@@ -360,7 +373,16 @@ def app_url(app_server: str) -> str:
 
 def _seed(db: Session) -> None:
     """The phase-37 two-document pair, byte-identical (see the module
-    docstring)."""
+    docstring), plus the phase-94 registry rows: both sources
+    registered, ``Deployments`` FIRST — the mock's drill (first
+    source of the top-level listing) lands on the JSON file."""
+    # COMMIT between the inserts (not flush): ``added_at`` is
+    # ``server_default now()`` — the transaction timestamp — and the
+    # tie-break is the random uuid ``id``, so one-transaction rows order
+    # nondeterministically.
+    db.add(GitSource(url=READ_SOURCE, kind="local"))
+    db.commit()
+    db.add(GitSource(url=SEED_SOURCE, kind="local"))
     md = Document(
         source=SEED_SOURCE,
         path=SEED_PATH,
@@ -408,7 +430,7 @@ def _reset_db(seed: Callable[[Session], None] | None = None) -> None:
         db.execute(
             text(
                 "TRUNCATE chunks, documents, query_log, "
-                "steering_notes, kb_overview, saved_chats"
+                "steering_notes, kb_overview, saved_chats, git_sources"
             )
         )
         db.commit()
@@ -514,7 +536,7 @@ def _wait_settled(page: Page) -> None:
 
 #: The FIRST tool line's suffix, pinned to the line ("first .tool-call
 #: child of the .tool-calls container" — the "Listing documents" line;
-#: the read frame's second line arms its OWN clock 5 s later and is
+#: the drill frame's second line arms its OWN clock 5 s later and is
 #: never the target here).
 FIRST_LINE_SUFFIX = "#messages .tool-calls .tool-call:first-child .tool-elapsed"
 
@@ -611,8 +633,8 @@ def test_typing_indicator_shows_visible_elapsed(
     )
 
     # The clock ticks while the gap holds: ≥1.5 s later the value is
-    # strictly greater (the read frame is ≥6 s away; the first delta
+    # strictly greater (the drill frame is ≥6 s away; the first delta
-    # — which removes the whole indicator — is ≈25 s from submit).
+    # — which removes the whole indicator — is ≈31 s from submit).
     page.wait_for_timeout(int(SAMPLE_GAP_S * 1000))
     v2 = _elapsed_value(
         page.locator("#typing-indicator .typing-elapsed").first.text_content(),
@@ -644,7 +666,7 @@ def test_indicators_settle_when_the_answer_arrives(
     # First the ticking state (the test-1 wait, reused)…
     expect(page.locator(FIRST_LINE_SUFFIX)).to_be_visible(timeout=SUFFIX_TIMEOUT_MS)
 
-    # …then the answer arrives (≈25 s from submit — see the module
+    # …then the answer arrives (≈31 s from submit — see the module
     # docstring's timeline) and settles.
     _wait_settled(page)
 
@@ -661,13 +683,16 @@ def test_indicators_settle_when_the_answer_arrives(
     expect(page.locator("#messages .tool-elapsed")).to_have_count(0)
     expect(page.locator("#typing-indicator")).to_have_count(0)
 
-    # The tool lines remain — the permanent record, both present with
+    # The tool lines remain — the permanent record, all three present
-    # their pinned text (phase 37's pattern).
+    # with their pinned text (phase 37's pattern + the phase-94 drill
+    # line).
     lines = page.locator("#messages .tool-call")
-    expect(lines).to_have_count(2)
+    expect(lines).to_have_count(3)
     expect(lines.nth(0)).to_contain_text("Listing documents")
-    expect(lines.nth(1)).to_contain_text("Reading ")
+    expect(lines.nth(1)).to_contain_text("Listing documents in")
-    expect(lines.nth(1)).to_contain_text(READ_SP)
+    expect(lines.nth(1)).to_contain_text(READ_SOURCE)
+    expect(lines.nth(2)).to_contain_text("Reading ")
+    expect(lines.nth(2)).to_contain_text(READ_SP)
 
     # The answer bubble is complete (the mock's deterministic quote).
     bubble = page.locator(".msg.brain .bubble").last
@@ -705,12 +730,14 @@ def test_restored_turn_has_no_timer(
     expect(page.locator("#empty-state")).to_be_hidden(timeout=RESTORE_TIMEOUT_MS)
 
     # The persisted record re-renders the tool lines, in saved order
-    # (the phase-37 reload pin, mirrored)…
+    # (the phase-37 reload pin, mirrored + the phase-94 drill line)…”
     restored = page.locator("#messages .tool-call")
-    expect(restored).to_have_count(2, timeout=RESTORE_TIMEOUT_MS)
+    expect(restored).to_have_count(3, timeout=RESTORE_TIMEOUT_MS)
     expect(restored.nth(0)).to_contain_text("Listing documents")
-    expect(restored.nth(1)).to_contain_text("Reading ")
+    expect(restored.nth(1)).to_contain_text("Listing documents in")
-    expect(restored.nth(1)).to_contain_text(READ_SP)
+    expect(restored.nth(1)).to_contain_text(READ_SOURCE)
+    expect(restored.nth(2)).to_contain_text("Reading ")
+    expect(restored.nth(2)).to_contain_text(READ_SP)
 
     # …with NO timer (A6 — the restore never arms the clock) and the
     # page otherwise settled.

tests/e2e/test_harness_aligned_tools.py

@@ -13,9 +13,13 @@ deterministic marker flows in ``tests/e2e/mock_llm.py`` (phase 70: the
 flows emit the NEW names with the NEW argument shapes):
 
 * the READ flow (``use your tools`` (``TOOLS_TRIGGER``) + the HIGH
-  prompt's ``<tools>`` section): ``ls`` (id ``call_0``, no arguments) →
+  prompt's ``<tools>`` section; phase 94: the drill-down ``ls`` — the
-  ``read`` on the JOINED combined ``source/path`` of the first catalog
+  top level lists sources only, so the flow drills one level before the
-  line (id ``call_1``) → the ``Read <source/path>. <quote>`` answer;
+  first file line exists): ``ls`` (id ``call_0``, no arguments) → the
+  drill ``ls`` scoped to the first source of the listing
+  (id ``call_1``) → ``read`` on the JOINED combined ``source/path`` of
+  the first file line (id ``call_2``) → the ``Read <source/path>.
+  <quote>`` answer;
 * the SEARCH flow (``search your documents`` (``SEARCH_TRIGGER``) + the
   ``<tools>`` section): ``grep`` with ``{"pattern": SEARCH_PATTERN}``
   (id ``call_0``) → the ``Found <matched line>`` answer.
@@ -41,13 +45,14 @@ KB fixtures:
 
 Test → phase mapping (Playwright Mapping Rule):
 1. ``test_read_flow_lines_answer_sources_no_raw_markup`` — the
-   grounded READ turn: the UI shows the ``ls`` line (unscoped "🔎
+   grounded READ turn: the UI shows the unscoped ``ls`` line ("🔎
-   Listing documents", no argument) then the "📄 Reading <source/path>"
+   Listing documents", no argument), the drill line ("🔎 Listing
-   line with the combined path in a ``<code>`` element, the answer
+   documents in <source>" — phase 94, the source in a ``<code>``
-   streams and quotes the read document, the done-state sources
+   element), then the "📄 Reading <source/path>" line with the
-   include the read document, and NO raw tool markup (``<|…|>``,
+   combined path in a ``<code>`` element, the answer streams and quotes
-   ``tool_call``) appears anywhere in the DOM — the live incident this
+   the read document, the done-state sources include the read document,
-   phase fixes.
+   and NO raw tool markup (``<|…|>``, ``tool_call``) appears anywhere
+   in the DOM — the live incident this phase fixes.
 2. ``test_grep_flow_line_then_answer`` — the grounded SEARCH turn: the
    "🔎 Searching for <pattern>" line (sentinel in ``<code>``) then the
    matched-line answer.
@@ -74,7 +79,7 @@ from sqlalchemy.orm import Session
 
 from app.config import Settings
 from app.db import SessionLocal
-from app.models import Chunk, Document
+from app.models import Chunk, Document, GitSource
 from app.rag.importer import ImportSummary, import_sources
 from app.rag.llm import LLMClient
 from e2e.auth_helpers import login
@@ -156,7 +161,22 @@ READ_ANSWER_QUOTE = RECORD_FILE_CONTENT[:80]
 
 
 def _seed_read_pair(db: Session) -> None:
-    """The two-document READ-flow KB (see the module docstring)."""
+    """The two-document READ-flow KB (see the module docstring).
+
+    Phase 94: the drill-down ``ls`` top level reads the registry —
+    register BOTH sources (TRUNCATEd in ``_reset_db_read_pair``),
+    ``Deployments`` FIRST (registry order ``(added_at, id)``): the
+    mock's drill (first source of the listing) lands on the JSON file
+    — the read the assertions expect. A non-empty table also ignores
+    the operator's ``BOR_GIT_SOURCES`` fallback — deterministic.
+    """
+    # COMMIT between the inserts (not flush): ``added_at`` is
+    # ``server_default now()`` — the transaction timestamp — and the
+    # tie-break is the random uuid ``id``, so one-transaction rows order
+    # nondeterministically.
+    db.add(GitSource(url=READ_SOURCE, kind="local"))
+    db.commit()
+    db.add(GitSource(url=SEED_SOURCE, kind="local"))
     md = Document(
         source=SEED_SOURCE,
         path=SEED_PATH,
@@ -267,7 +287,10 @@ def _reset_db_read_pair() -> None:
     answers."""
     with SessionLocal() as db:
         db.execute(
-            text("TRUNCATE chunks, documents, query_log, steering_notes, kb_overview")
+            text(
+                "TRUNCATE chunks, documents, query_log, steering_notes, "
+                "kb_overview, git_sources"
+            )
         )
         db.commit()
         _seed_read_pair(db)
@@ -386,15 +409,18 @@ def test_read_flow_lines_answer_sources_no_raw_markup(
     _submit(page, READ_QUESTION)
     _wait_settled(page)
 
-    # The UI shows the ls line (UNSCOPED — no argument, no <code>) then
+    # The UI shows the ls line (UNSCOPED — no argument, no <code>),
+    # the drill line (phase 94 — the source in a <code> element), then
     # the "📄 Reading <source/path>" line with the COMBINED path in a
     # <code> element (the path is data, never markup).
     lines = page.locator(".msg.brain .tool-call")
-    expect(lines).to_have_count(2)
+    expect(lines).to_have_count(3)
     expect(lines.nth(0)).to_contain_text("Listing documents")
     expect(lines.nth(0).locator("code")).to_have_count(0)
-    expect(lines.nth(1)).to_contain_text("Reading ")
+    expect(lines.nth(1)).to_contain_text("Listing documents in")
-    expect(lines.nth(1).locator("code")).to_have_text(READ_SP)
+    expect(lines.nth(1).locator("code")).to_have_text(READ_SOURCE)
+    expect(lines.nth(2)).to_contain_text("Reading ")
+    expect(lines.nth(2).locator("code")).to_have_text(READ_SP)
 
     # The answer streamed and quotes the read document (the mock's
     # deterministic echo: "Read <source/path>. <first 80 chars>").
@@ -402,12 +428,14 @@ def test_read_flow_lines_answer_sources_no_raw_markup(
     expect(bubble).to_contain_text(READ_ANSWER_PREFIX)
     expect(bubble).to_contain_text(READ_ANSWER_QUOTE)
 
-    # Wire level: ls then read — the phase-70 argument rule (ls
+    # Wire level: ls, the drill ls scoped to the first source (phase
-    # unscoped → null; read → the combined path as passed) — ahead of
+    # 94), then read — the phase-70 argument rule (ls unscoped → null;
-    # the first delta.
+    # scoped ls → the source name; read → the combined path as passed)
+    # — ahead of the first delta.
     frames = _drain_frames(page)
     assert _tool_frames(frames) == [
         {"type": "tool", "name": "ls", "argument": None},
+        {"type": "tool", "name": "ls", "argument": READ_SOURCE},
         {"type": "tool", "name": "read", "argument": READ_SP},
     ]
     first_delta = next(i for i, f in enumerate(frames) if f.get("type") == "delta")
@@ -508,10 +536,12 @@ def test_wire_argument_rule_across_both_flows(
     read_tools = _tool_frames(read_frames)
     search_tools = _tool_frames(search_frames)
     # The ordered, combined tool-frame sequence across both flows: the
-    # argument rule end-to-end — read → the combined path as passed,
+    # argument rule end-to-end — the drill ls (phase 94) → the source
-    # grep → the pattern, ls → null when unscoped.
+    # name, read → the combined path as passed, grep → the pattern,
+    # ls → null when unscoped.
     assert read_tools + search_tools == [
         {"type": "tool", "name": "ls", "argument": None},
+        {"type": "tool", "name": "ls", "argument": READ_SOURCE},
         {"type": "tool", "name": "read", "argument": READ_SP},
         {"type": "tool", "name": "grep", "argument": SEARCH_PATTERN},
     ]

tests/e2e/test_ls_tree_drilldown.py

@@ -0,0 +1,772 @@
+"""Phase 94 task 04 E2E (Playwright, mock-only): the ``ls`` drill-down tree.
+
+The dedicated story suite for ``94_ls_tree_drilldown`` (owner TODO.md L4):
+the LLM drills ``ls()`` → ``ls(source)`` → ``ls(source/folder)`` →
+``read(source/file)`` through the real UI, the sync-time folder summaries
+(must exist after a changed sync under the deterministic mock's
+``FOLDER_SUMMARY_MODE`` branch) show up in the ``ls`` output, and the
+50-line cap holds on a wide folder.
+
+Run in isolation (DB must be up: ``podman compose up -d db``):
+
+    uv run pytest tests/e2e/test_ls_tree_drilldown.py -v --no-cov
+
+MOCK-ONLY suite: ``E2E_REAL_LLM=1`` is not supported — the real ``turbo``
+does whatever it does with the tools, while this story's gate is the
+deterministic SCRIPTED drill-down flow in ``tests/e2e/mock_llm.py``
+(``DRILL_TRIGGER``: user message contains ``drill down the tree`` —
+the question carries its own tool call after the colon,
+``drill down the tree: ls [target]`` / ``drill down the tree: read
+source/path`` — **and** the system prompt carries the ``<tools>``
+section of the HIGH prompt). The mock echoes the received tool result
+into its final answer (the house scripted-turn way of asserting on tool
+results — the mock is the only E2E lens on the LLM's context), so every
+tree-level assertion below lands on the rendered answer; the DOM
+assertions cover the tool lines + the answer.
+
+KB fixture — a host temp dir tree (``tmp_path_factory``; the app runs on
+the same host) with TWO registered local sources (the
+``test_local_directory_sources.py`` registration + real-Sync pattern —
+registration through the authenticated API, the real in-process
+``POST /api/sync`` pipeline; no git anywhere):
+
+* ``alpha/`` — ``root-note.md`` at the source root, ``one/`` (2 docs),
+  ``two/`` (2 docs — the read target lives here) and ``wide/`` (51 tiny
+  files — the 50-line cap subject);
+* ``beta/`` — ``gamma/`` (2 docs).
+
+Every fixture doc carries the words ``drill down the tree`` in its body,
+so every scripted question (which contains the trigger phrase) FTS-matches
+at least one chunk — the honesty gate is HIGH for all turns regardless
+of the mock's cosine distribution, and the ``<tools>`` section is present
+(the flow's precondition).
+
+The mock's canned ``FOLDER_SUMMARY_MODE`` branch (phase 94 task 01)
+stores, per ≥ 2-doc folder, the deterministic one-liner
+``Fixture folder summary for <source>[/<folder>].`` — the ``synced_kb``
+module fixture pins those exact rows in ``folder_summaries`` after the
+sync, and the drill answers assert on them in the ``ls`` output.
+
+Test → story mapping (Playwright Mapping Rule):
+1. ``test_drill_down_sources_folders_files_and_read`` — the four
+   scripted turns: ``ls()`` (the ``🔎 Listing documents`` line + the
+   top-level shape — one ``— N documents`` line per source + the
+   canned source-root summaries), ``ls(alpha)`` (folder lines with
+   their summaries + the root file line), ``ls(alpha/two)`` (the exact
+   ``source: X | path: Y | title: Z`` file lines), and the grounded
+   ``read(alpha/two/two-a.md)`` (the ``📄 Reading …`` line + the answer
+   citing the document, the phase-37 assertion pattern). The read
+   target is DELIBERATELY a top-2 retrieval document for its question
+   (the question names the file's path, so the file self-matches the
+   hybrid gate deterministically): the agent's phase-72 dedupe returns
+   ``ALREADY_IN_CONTEXT`` (a refusal — counts in nothing), and the
+   mock answers FROM THE ``<documents>`` PROMPT with the same citation
+   shape (``Already in context: Read <sp>. <first 80 chars>``) — the
+   document text reached the model either way, and the prefix pins
+   that the dedupe notice itself reached it.
+2. ``test_wide_folder_holds_the_fifty_line_cap`` — ``ls(alpha/wide)``
+   on the 51-file folder: the mock's echo carries exactly 50 file lines
+   + the ``…and 1 more documents in this folder — use grep (pattern)…``
+   note; the 51st file never reaches the model.
+3. ``test_not_a_folder_teaching_and_scripted_recovery`` — the mock calls
+   ``ls(alpha/nope)``; the NOT-A-FOLDER teaching line (the argument
+   echoed, the parent's subfolders listed) is visible to the model —
+   the mock's scripted recovery branch keys on receiving it — and the
+   scripted ``ls(alpha)`` recovery lands (the answer is the parent's
+   listing; the loop ends in one refusal + one correction, not at the
+   round cap).
+"""
+from __future__ import annotations
+
+import json
+import os
+import re
+import subprocess
+import sys
+import time
+from collections.abc import Iterator
+from pathlib import Path
+from typing import Any
+
+import httpx
+import pytest
+from playwright.sync_api import Locator, Page, expect
+from sqlalchemy import select, text
+
+from app.config import Settings as _Settings
+from app.db import SessionLocal
+from app.models import FolderSummary, QueryLog
+from e2e.auth_helpers import login
+from e2e.conftest import (
+    ADMIN_PASSWORD,
+    SESSION_SECRET,
+    USE_REAL_LLM,
+    _wait_http,
+)
+
+REPO = Path(__file__).resolve().parents[2]
+
+# Phase 79 (task 04, full inventory): the conftest session app owns its
+# port in a combined run — this module app binds its own port instead
+# (a same-port second uvicorn dies on bind and would drive the wrong
+# server). Env-overridable.
+APP_PORT = int(os.environ.get("E2E_APP_PORT_LSTREE", "8136"))
+APP_URL = f"http://127.0.0.1:{APP_PORT}"
+
+# --------------------------------------------------------------------------
+# Fixture documents (deterministic, token-controlled)
+# --------------------------------------------------------------------------
+
+ALPHA = "alpha"
+BETA = "beta"
+
+ROOT_NOTE = "root-note.md"
+TWO_A = "two/two-a.md"
+TWO_B = "two/two-b.md"
+READ_SP = f"{ALPHA}/{TWO_A}"
+
+ALPHA_COUNT = 56  # 1 root note + 2 one/ + 2 two/ + 51 wide/
+BETA_COUNT = 2
+TOTAL_DOCS = ALPHA_COUNT + BETA_COUNT
+WIDE_COUNT = 51
+LS_MAX_FILE_LINES = 50  # app.rag.agent.LS_MAX_FILE_LINES — the cap under test
+
+#: Every fixture body carries ``drill down the tree`` (the trigger
+#: phrase's words): every scripted question FTS-matches at least one
+#: chunk → HIGH gate → the ``<tools>`` section the flow keys on.
+DRILL_LEAD = "The drill down the tree fixture note"
+
+
+def _md(title: str, body: str) -> str:
+    return f"# {title}\n\n{body}\n"
+
+
+#: The read target — its FIRST line is ≥ 80 chars, so the mock's
+#: first-80-chars quote (the phase-37 single-read shape) is newline-free
+#: and the rendered-text assertion matches it verbatim. Pinned by the
+#: assert below.
+TWO_A_TITLE = (
+    "Alpha Two A — the drill-down read target for the alpha two folder "
+    "listing turn in the brain of reese fixture"
+)
+TWO_A_CONTENT = _md(
+    TWO_A_TITLE,
+    f"{DRILL_LEAD} for alpha two: this document covers topic A of the "
+    "alpha source tree; it is the file the scripted read turn opens "
+    "from the alpha/two listing.",
+)
+assert "\n" not in TWO_A_CONTENT[:80]  # the quote must stay one line
+
+#: The sync-time folder summaries the mock's canned ``FOLDER_SUMMARY_MODE``
+#: branch stores (task 01's byte-stable template), in
+#: ``(source, folder_path)`` order: one row per ≥ 2-doc folder (the
+#: recursive-subtree rule) — the ``""`` rows are the source roots.
+EXPECTED_SUMMARIES: list[tuple[str, str, str]] = [
+    (ALPHA, "", f"Fixture folder summary for {ALPHA}."),
+    (ALPHA, "one", f"Fixture folder summary for {ALPHA}/one."),
+    (ALPHA, "two", f"Fixture folder summary for {ALPHA}/two."),
+    (ALPHA, "wide", f"Fixture folder summary for {ALPHA}/wide."),
+    (BETA, "", f"Fixture folder summary for {BETA}."),
+    (BETA, "gamma", f"Fixture folder summary for {BETA}/gamma."),
+]
+assert [
+    (source, folder) for source, folder, _s in EXPECTED_SUMMARIES
+] == sorted((source, folder) for source, folder, _s in EXPECTED_SUMMARIES)
+
+# --- the pinned tree levels (app.rag.agent's phase-94 templates) -------
+
+#: ``ls()`` — the top level: sources in registry order (alpha registered
+#: first), each with its recursive count + stored source-root summary.
+TOP_HEADER = "2 sources:"
+TOP_LINES = [
+    f"{ALPHA} — {ALPHA_COUNT} documents",
+    EXPECTED_SUMMARIES[0][2],
+    f"{BETA} — {BETA_COUNT} documents",
+    EXPECTED_SUMMARIES[4][2],
+]
+
+#: ``ls(alpha)`` — the source root: the subfolder lines (path order)
+#: with their stored summaries, then the root's own file line (the
+#: canonical ``read``/``grep`` identity format, unchanged).
+SOURCE_HEADER = f"{ALPHA} — 1 documents, 3 folders:"
+SOURCE_LINES = [
+    f"one/ — 2 documents: {EXPECTED_SUMMARIES[1][2]}",
+    f"two/ — 2 documents: {EXPECTED_SUMMARIES[2][2]}",
+    f"wide/ — {WIDE_COUNT} documents: {EXPECTED_SUMMARIES[3][2]}",
+    f"source: {ALPHA} | path: {ROOT_NOTE} | title: Alpha Root Note",
+]
+
+#: ``ls(alpha/two)`` — a leaf folder: the file lines in EXACTLY the
+#: existing ``source: X | path: Y | title: Z`` format, path order.
+FOLDER_HEADER = f"{ALPHA}/two — 2 documents, 0 folders:"
+FOLDER_LINES = [
+    f"source: {ALPHA} | path: {TWO_A} | title: {TWO_A_TITLE}",
+    f"source: {ALPHA} | path: {TWO_B} | title: Alpha Two B",
+]
+
+#: ``ls(alpha/wide)`` — the 50-line cap: 51 files → 50 lines (path
+#: order: wide-01 … wide-50) + one deterministic grep-pointer note;
+#: wide-51 never reaches the model.
+WIDE_HEADER = f"{ALPHA}/wide — {WIDE_COUNT} documents, 0 folders:"
+WIDE_FIRST = f"source: {ALPHA} | path: wide/wide-01.md | title: Wide 01"
+WIDE_LAST = f"source: {ALPHA} | path: wide/wide-50.md | title: Wide 50"
+WIDE_NOTE = (
+    "…and 1 more documents in this folder — use grep "
+    "(pattern) to find a specific one."
+)
+
+# --- the scripted turns (the mock's ``DRILL_TRIGGER`` questions) -------
+
+TOP_QUESTION = "Drill down the tree: ls — what sources are indexed?"
+SOURCE_QUESTION = f"Drill down the tree: ls {ALPHA} — what's in source {ALPHA}?"
+FOLDER_QUESTION = f"Drill down the tree: ls {ALPHA}/two — list that folder"
+READ_QUESTION = f"Drill down the tree: read {READ_SP} — read the file"
+WIDE_QUESTION = f"Drill down the tree: ls {ALPHA}/wide — how many files does this folder hold?"
+NOPE_QUESTION = f"Drill down the tree: ls {ALPHA}/nope — is there such a folder?"
+
+#: The read target is a top-2 retrieval document for its question (the
+#: question names the path — the file self-matches the hybrid gate
+#: deterministically), so the read gets the phase-72 ALREADY_IN_CONTEXT
+#: dedupe and the mock answers from the ``<documents>`` prompt with the
+#: same citation shape, prefixed (the suite pins the dedupe path).
+READ_ANSWER_PREFIX = f"Already in context: Read {READ_SP}."
+READ_ANSWER_QUOTE = TWO_A_CONTENT[:80]
+
+# --------------------------------------------------------------------------
+# Fixtures
+# --------------------------------------------------------------------------
+
+
+@pytest.fixture(scope="module")
+def drill_dirs(tmp_path_factory: pytest.TempPathFactory) -> tuple[Path, Path]:
+    """The two-source temp tree (see the module docstring): the app
+    server runs on the same host, so the paths are visible to it. The
+    directory NAMES are the source names (``kind=local`` → the
+    directory's basename, phase 38)."""
+    root = tmp_path_factory.mktemp("bor_ls_tree")
+    alpha = root / ALPHA
+    beta = root / BETA
+    (alpha / "one").mkdir(parents=True)
+    (alpha / "two").mkdir(parents=True)
+    (alpha / "wide").mkdir(parents=True)
+    (beta / "gamma").mkdir(parents=True)
+
+    (alpha / ROOT_NOTE).write_text(
+        _md(
+            "Alpha Root Note",
+            f"{DRILL_LEAD} at the alpha source root: this file sits "
+            "directly under the alpha source, not in any folder.",
+        ),
+        encoding="utf-8",
+    )
+    (alpha / "one" / "one-a.md").write_text(
+        _md(
+            "Alpha One A",
+            f"{DRILL_LEAD} for alpha one: this document covers topic A "
+            "of the alpha source tree.",
+        ),
+        encoding="utf-8",
+    )
+    (alpha / "one" / "one-b.md").write_text(
+        _md(
+            "Alpha One B",
+            f"{DRILL_LEAD} for alpha one: this document covers topic B "
+            "of the alpha source tree.",
+        ),
+        encoding="utf-8",
+    )
+    (alpha / TWO_A).write_text(TWO_A_CONTENT, encoding="utf-8")
+    (alpha / TWO_B).write_text(
+        _md(
+            "Alpha Two B",
+            f"{DRILL_LEAD} for alpha two: this document covers topic B "
+            "of the alpha source tree.",
+        ),
+        encoding="utf-8",
+    )
+    for nn in range(1, WIDE_COUNT + 1):
+        (alpha / "wide" / f"wide-{nn:02d}.md").write_text(
+            _md(
+                f"Wide {nn:02d}",
+                f"One of {WIDE_COUNT} tiny files in the alpha wide "
+                f"folder: {DRILL_LEAD.lower()} line {nn:02d}.",
+            ),
+            encoding="utf-8",
+        )
+    (beta / "gamma" / "gamma-a.md").write_text(
+        _md(
+            "Beta Gamma A",
+            f"{DRILL_LEAD} for beta gamma: this document covers topic A "
+            "of the beta source tree.",
+        ),
+        encoding="utf-8",
+    )
+    (beta / "gamma" / "gamma-b.md").write_text(
+        _md(
+            "Beta Gamma B",
+            f"{DRILL_LEAD} for beta gamma: this document covers topic B "
+            "of the beta source tree.",
+        ),
+        encoding="utf-8",
+    )
+    assert (alpha / TWO_A).is_file() and (beta / "gamma" / "gamma-b.md").is_file()
+    return alpha, beta
+
+
+@pytest.fixture(scope="module")
+def app_server(mock_llm: int, drill_dirs: tuple[Path, Path]) -> Iterator[str]:
+    """The real app under test — per-module app (the conftest pattern,
+    cf. ``test_local_directory_sources.py``): NO ``BOR_GIT_SOURCES``
+    (the env fallback is git-only — the sources here are DB-registered
+    local directories), the mock LLM, the mock-calibrated threshold,
+    and the leak-guarded code defaults. The session app is never
+    started in this isolated run, so no port clash."""
+    env = dict(os.environ)
+    env.pop("DEBUGPY", None)
+    env["BOR_ENVIRONMENT"] = "e2e"
+    env["BOR_STATIC_DIR"] = str(REPO / "frontend")
+    env["BOR_LLM_BASE_URL"] = (
+        "https://aipi.reeseapps.com/v1"
+        if USE_REAL_LLM
+        else f"http://127.0.0.1:{mock_llm}/v1"
+    )
+    # Mock-calibrated threshold (conftest pattern): every scripted
+    # question FTS-matches the fixture docs (the ``drill down the tree``
+    # words), so the gate is HIGH either way.
+    env["BOR_RELEVANCE_THRESHOLD"] = "0.30"
+    # Phase 67: instant retry waits + the code-default budget (the
+    # conftest leak-guard pattern).
+    env["BOR_LLM_RETRY_DELAY"] = "0"
+    env["BOR_LLM_RETRIES"] = str(_Settings.model_fields["llm_retries"].default)
+    env.setdefault(
+        "BOR_DATABASE_URL",
+        "postgresql+psycopg://reese:reese@localhost:5432/brain_of_reese",
+    )
+    # Phase 16: admin auth must be set or create_app() refuses to boot.
+    env["BOR_ADMIN_PASSWORD"] = ADMIN_PASSWORD
+    env["BOR_SESSION_SECRET"] = SESSION_SECRET
+    # The repo's .env file carries the owner's BOR_GIT_SOURCES (the app
+    # reads it from cwd) — override it with an EMPTY value (the env var
+    # beats the .env file): the registry must hold EXACTLY the two
+    # local directories this suite registers (a leftover env git list
+    # would pollute the top-level ``ls`` the whole story asserts on).
+    env["BOR_GIT_SOURCES"] = ""
+    # Leak guards (conftest pattern): an operator's local (gitignored)
+    # .env cannot leak corpus-specific settings into the app under test.
+    env["BOR_DOCS_REPO"] = ""
+    env["BOR_SUGGESTIONS"] = json.dumps(
+        _Settings.model_fields["suggestions"].default
+    )
+    env["BOR_INPUT_PLACEHOLDER"] = _Settings.model_fields["input_placeholder"].default
+    env["BOR_FOOTER_TEXT"] = _Settings.model_fields["footer_text"].default
+    proc = subprocess.Popen(
+        [sys.executable, "-m", "uvicorn", "app.main:app",
+         "--host", "127.0.0.1", "--port", str(APP_PORT), "--log-level", "warning"],
+        cwd=REPO,
+        env=env,
+    )
+    try:
+        _wait_http(f"{APP_URL}/api/health")
+        yield APP_URL
+    finally:
+        proc.terminate()
+        try:
+            proc.wait(timeout=10)
+        except subprocess.TimeoutExpired:
+            proc.kill()
+
+
+@pytest.fixture(scope="module")
+def app_url(app_server: str) -> str:
+    return app_server
+
+
+def _truncate_all() -> None:
+    """Fresh registry + KB (the E2E isolation pattern): the E2E suites
+    share one Postgres, so a leftover git_sources row would pollute the
+    top-level ``ls`` and a leftover document would show up in the
+    folder listings the drill answers assert on byte-exactly."""
+    with SessionLocal() as db:
+        db.execute(
+            text(
+                "TRUNCATE chunks, documents, query_log, steering_notes, "
+                "kb_overview, git_sources, folder_summaries"
+            )
+        )
+        db.commit()
+
+
+def _wait_sync_done_http(client: httpx.Client, timeout_s: float = 180.0) -> dict[str, Any]:
+    """Poll the (cookie-authenticated) status endpoint until the run
+    reaches a terminal state (the test_local_directory_sources pattern,
+    over plain httpx — this fixture has no browser page yet)."""
+    deadline = time.monotonic() + timeout_s
+    body: dict[str, Any] = {}
+    while time.monotonic() < deadline:
+        r = client.get("/api/sync/status")
+        assert r.status_code == 200, r.text
+        body = r.json()
+        if body["state"] in ("success", "failed"):
+            return body
+        time.sleep(0.5)
+    raise AssertionError(f"sync did not reach a terminal state: {body}")
+
+
+@pytest.fixture(scope="module")
+def synced_kb(app_server: str, drill_dirs: tuple[Path, Path]) -> None:
+    """The story's precondition: the folder-structured KB synced under
+    the deterministic mock.
+
+    Registers the two temp directories through the authenticated API
+    (the ``test_local_directory_sources.py`` pattern — ``alpha`` FIRST,
+    committed separately, so the registry order — ``(added_at, id)`` —
+    lists alpha before beta, the top-level ``ls`` order the suite
+    asserts), runs the REAL in-process sync (``POST /api/sync`` —
+    walk → chunk → embed → overview → folder summaries → version bump),
+    and pins the stored folder summaries: the mock's canned
+    ``FOLDER_SUMMARY_MODE`` branch (task 01) makes the sync store one
+    deterministic row per ≥ 2-doc folder — the drill turns' answers
+    assert on that exact text.
+    """
+    alpha, beta = drill_dirs
+    _truncate_all()
+    with httpx.Client(base_url=app_server, timeout=30.0) as client:
+        r = client.post("/api/login", json={"password": ADMIN_PASSWORD})
+        assert r.status_code == 204, r.text
+        r = client.post(
+            "/api/git-sources", json={"kind": "local", "path": str(alpha)}
+        )
+        assert r.status_code == 201, r.text
+        time.sleep(0.05)  # distinct added_at: alpha before beta (registry order)
+        r = client.post(
+            "/api/git-sources", json={"kind": "local", "path": str(beta)}
+        )
+        assert r.status_code == 201, r.text
+        r = client.post("/api/sync")
+        assert r.status_code == 202, r.text
+        body = _wait_sync_done_http(client)
+    assert body["state"] == "success", body
+    detail = body["detail"]
+    assert detail["added"] == TOTAL_DOCS, detail
+    assert detail["pruned"] == 0, detail
+    assert detail["overview"] is True, detail
+    # The change-gated folder summaries (phase 94 task 02) landed: one
+    # row per ≥ 2-doc folder, the mock's byte-stable text (the drill
+    # answers quote exactly these lines).
+    with SessionLocal() as db:
+        rows = db.execute(
+            select(
+                FolderSummary.source, FolderSummary.folder_path,
+                FolderSummary.summary,
+            ).order_by(FolderSummary.source, FolderSummary.folder_path)
+        ).all()
+    assert [(s, f, t) for s, f, t in rows] == EXPECTED_SUMMARIES, rows
+
+
+@pytest.fixture(autouse=True)
+def _clean(db_ready: None) -> Iterator[None]:
+    """Per-test query_log isolation (the KB itself is module-scoped —
+    the drill turns never change it, so the folder summaries and the
+    registry persist across the tests of this module)."""
+    with SessionLocal() as db:
+        db.execute(text("TRUNCATE query_log"))
+        db.commit()
+    yield
+    with SessionLocal() as db:
+        db.execute(text("TRUNCATE query_log"))
+        db.commit()
+
+
+# --------------------------------------------------------------------------
+# Page helpers (the test_agent_document_tools house pattern)
+# --------------------------------------------------------------------------
+
+#: Captures the raw SSE ``data:`` payloads of the /api/chat stream
+#: (a response clone read in the background) — wire-level assertions
+#: for the ``tool`` frames, independent of the UI rendering.
+SSE_HOOK = """
+() => {
+  if (window.__sseInstalled) return;
+  window.__sseInstalled = true;
+  window.__sseFrames = [];
+  const origFetch = window.fetch;
+  window.fetch = async function (...args) {
+    const res = await origFetch.apply(this, args);
+    try {
+      const url = typeof args[0] === 'string' ? args[0] : args[0].url;
+      if (url.includes('/api/chat')) {
+        res.clone().text().then((bodyText) => {
+          for (const block of bodyText.split('\\n\\n')) {
+            const line = block.trim();
+            if (line.startsWith('data: ')) {
+              window.__sseFrames.push(line.slice(6));
+            }
+          }
+        });
+      }
+    } catch (e) { /* non-clonable responses: ignored */ }
+    return res;
+  };
+}
+"""
+
+
+def _install_page_hooks(page: Page) -> None:
+    page.evaluate(SSE_HOOK)
+
+
+def _frames(page: Page) -> list[dict]:
+    """The SSE frames captured since the last submit (``_submit``
+    clears the buffer), once the hook's background read settles."""
+    deadline = time.monotonic() + 30.0
+    while True:
+        raw = page.evaluate("() => window.__sseFrames || []")
+        parsed = [json.loads(line) for line in raw if line]
+        if any(f.get("type") == "done" for f in parsed):
+            return parsed
+        if time.monotonic() > deadline:
+            raise AssertionError(
+                f"SSE hook captured no `done` frame (frames so far: "
+                f"{len(parsed)}) — hook install failed?"
+            )
+        time.sleep(0.05)
+
+
+def _tool_frames(frames: list[dict]) -> list[dict]:
+    return [f for f in frames if f.get("type") == "tool"]
+
+
+def _submit(page: Page, question: str) -> None:
+    page.evaluate("window.__sseFrames = []")
+    page.fill("#message-input", question)
+    page.click("#send-btn")
+    # The user bubble lands synchronously with the submit handler.
+    expect(page.locator(".msg.user .bubble").last).to_contain_text(question)
+
+
+def _wait_settled(page: Page) -> None:
+    """The turn is complete: answer text in the bubble, button recovered
+    (the phase-48 settle wait, the test_agent_document_tools helper)."""
+    expect(page.locator(".msg.brain .bubble").last).not_to_have_text("", timeout=30_000)
+    expect(page.locator("#send-btn")).to_be_enabled(timeout=30_000)
+    expect(page.locator("#send-label")).to_have_text("Send", timeout=30_000)
+
+
+def _last_brain(page: Page) -> Locator:
+    return page.locator(".msg.brain").last
+
+
+def _assert_turn(
+    page: Page,
+    expected_tools: list[dict[str, Any]],
+    expected_answer_lines: list[str],
+) -> None:
+    """One scripted drill turn, fully asserted: the wire carries exactly
+    the expected ``tool`` frames (ahead of the first ``delta``), the
+    bubble carries the expected answer lines (the mock's echo of the
+    tool results the model received), and the turn was grounded (the
+    ``done`` frame is not deflected)."""
+    frames = _frames(page)
+    assert _tool_frames(frames) == expected_tools, _tool_frames(frames)
+    if expected_tools:
+        first_delta = next(
+            i for i, f in enumerate(frames) if f.get("type") == "delta"
+        )
+        assert all(
+            i < first_delta
+            for i, f in enumerate(frames)
+            if f.get("type") == "tool"
+        )
+    done = next(f for f in frames if f.get("type") == "done")
+    assert done["deflected"] is False, done
+    bubble = _last_brain(page).locator(".bubble")
+    for line in expected_answer_lines:
+        expect(bubble).to_contain_text(line)
+
+
+def _query_log_rows() -> list[QueryLog]:
+    with SessionLocal() as db:
+        return list(db.scalars(select(QueryLog)).all())
+
+
+# --------------------------------------------------------------------------
+# 1. The scripted drill: sources → folders (summaries) → files → read
+# --------------------------------------------------------------------------
+
+
+def test_drill_down_sources_folders_files_and_read(
+    page: Page, app_url: str, synced_kb: None, db_ready: None
+) -> None:
+    page.set_default_timeout(30_000)
+    login(page, app_url, next="/")
+    _install_page_hooks(page)
+
+    # --- turn 1: ls() — the top level (sources + source-root summaries) -
+    _submit(page, TOP_QUESTION)
+    _wait_settled(page)
+    lines = _last_brain(page).locator(".tool-call")
+    expect(lines).to_have_count(1)
+    # The no-arg ls line — NOT a scoped "Listing documents in …" one
+    # (regex match: string expectations normalize whitespace, so the
+    # scope check must be a byte-exact pattern).
+    expect(lines.nth(0)).to_contain_text("Listing documents")
+    expect(lines.nth(0)).not_to_have_text(re.compile(r"Listing documents in"))
+    _assert_turn(
+        page,
+        [{"type": "tool", "name": "ls", "argument": None}],
+        [TOP_HEADER, *TOP_LINES],
+    )
+
+    # --- turn 2: ls(alpha) — the source root (subfolders + root files) --
+    _submit(page, SOURCE_QUESTION)
+    _wait_settled(page)
+    lines = _last_brain(page).locator(".tool-call")
+    expect(lines).to_have_count(1)
+    expect(lines.nth(0)).to_contain_text(f"Listing documents in {ALPHA}")
+    _assert_turn(
+        page,
+        [{"type": "tool", "name": "ls", "argument": ALPHA}],
+        [SOURCE_HEADER, *SOURCE_LINES],
+    )
+
+    # --- turn 3: ls(alpha/two) — the folder level (the file lines) ------
+    _submit(page, FOLDER_QUESTION)
+    _wait_settled(page)
+    lines = _last_brain(page).locator(".tool-call")
+    expect(lines).to_have_count(1)
+    expect(lines.nth(0)).to_contain_text(f"Listing documents in {ALPHA}/two")
+    _assert_turn(
+        page,
+        [{"type": "tool", "name": "ls", "argument": f"{ALPHA}/two"}],
+        [FOLDER_HEADER, *FOLDER_LINES],
+    )
+
+    # --- turn 4: read(alpha/two/two-a.md) — the grounded read ------------
+    _submit(page, READ_QUESTION)
+    _wait_settled(page)
+    lines = _last_brain(page).locator(".tool-call")
+    expect(lines).to_have_count(1)
+    # The phase-37 "Reading <source/path>" line (the combined identity).
+    expect(lines.nth(0)).to_contain_text(f"Reading {READ_SP}")
+    frames = _frames(page)
+    assert _tool_frames(frames) == [
+        {"type": "tool", "name": "read", "argument": READ_SP}
+    ], _tool_frames(frames)
+    bubble = _last_brain(page).locator(".bubble")
+    # The dedupe notice reached the model (the prefix pins it — the read
+    # was refused as ALREADY_IN_CONTEXT because the target is a top-2
+    # retrieval document)…
+    expect(bubble).to_contain_text(READ_ANSWER_PREFIX)
+    # …and the answer still cites the document: the mock quotes the
+    # FIRST 80 chars of the target's text from the ``<documents>``
+    # prompt (the refusal's instruction — answer from that text; the
+    # quote is newline-free, pinned above).
+    expect(bubble).to_contain_text(READ_ANSWER_QUOTE)
+    done = next(f for f in frames if f.get("type") == "done")
+    assert done["deflected"] is False, done
+    # The read document is in the turn's sources (retrieval + agent-read,
+    # deduped — the grounded-turn record).
+    assert any(
+        s["path"] == TWO_A and s["source"] == ALPHA for s in done["sources"]
+    ), done["sources"]
+
+    # Durable records: all four turns grounded, in order, the read turn
+    # logging the read document.
+    rows = _query_log_rows()
+    assert [r.question for r in rows] == [
+        TOP_QUESTION, SOURCE_QUESTION, FOLDER_QUESTION, READ_QUESTION
+    ]
+    assert all(r.deflected is False for r in rows)
+    assert READ_SP in rows[3].sources, rows[3].sources
+
+
+# --------------------------------------------------------------------------
+# 2. The 50-line cap: a 51-file folder costs the model 50 lines + the note
+# --------------------------------------------------------------------------
+
+
+def test_wide_folder_holds_the_fifty_line_cap(
+    page: Page, app_url: str, synced_kb: None, db_ready: None
+) -> None:
+    page.set_default_timeout(30_000)
+    login(page, app_url, next="/")
+    _install_page_hooks(page)
+
+    _submit(page, WIDE_QUESTION)
+    _wait_settled(page)
+
+    lines = _last_brain(page).locator(".tool-call")
+    expect(lines).to_have_count(1)
+    expect(lines.nth(0)).to_contain_text(f"Listing documents in {ALPHA}/wide")
+
+    frames = _frames(page)
+    assert _tool_frames(frames) == [
+        {"type": "tool", "name": "ls", "argument": f"{ALPHA}/wide"}
+    ], _tool_frames(frames)
+    done = next(f for f in frames if f.get("type") == "done")
+    assert done["deflected"] is False, done
+
+    # The mock echoed the listing VERBATIM: the header carries the
+    # PRE-cap count (51 — the cap hides lines, not the truth), the
+    # file lines stop at 50, and the one deterministic grep-pointer note
+    # folds the 51st file away.
+    bubble = _last_brain(page).locator(".bubble")
+    text = bubble.text_content() or ""
+    assert WIDE_HEADER in text, text
+    assert WIDE_FIRST in text, text
+    assert WIDE_LAST in text, text
+    assert WIDE_NOTE in text, text
+    assert f"wide/wide-{WIDE_COUNT}.md" not in text, text  # the 51st file: gone
+    # Exactly LS_MAX_FILE_LINES file lines reached the model.
+    assert text.count(f"source: {ALPHA} | path: wide/") == LS_MAX_FILE_LINES, text
+
+    row = _query_log_rows()
+    assert len(row) == 1
+    assert row[0].deflected is False
+
+
+# --------------------------------------------------------------------------
+# 3. The NOT-A-FOLDER teaching is visible to the model; the scripted
+#    recovery (ls of the parent level) works
+# --------------------------------------------------------------------------
+
+
+def test_not_a_folder_teaching_and_scripted_recovery(
+    page: Page, app_url: str, synced_kb: None, db_ready: None
+) -> None:
+    page.set_default_timeout(30_000)
+    login(page, app_url, next="/")
+    _install_page_hooks(page)
+
+    _submit(page, NOPE_QUESTION)
+    _wait_settled(page)
+
+    # Two tool lines: the scripted misuse, then the scripted recovery —
+    # the mock's recovery branch fires ONLY when it RECEIVES the
+    # NOT-A-FOLDER teaching line (``'alpha/nope' is not a folder —
+    # alpha has: one/ two/ wide/`` — the argument echoed, the parent's
+    # subfolders listed): the teaching being visible to the model is
+    # exactly what the second call proves (the phase-72
+    # self-correction contract, now carrying the tree's teaching).
+    lines = _last_brain(page).locator(".tool-call")
+    expect(lines).to_have_count(2)
+    expect(lines.nth(0)).to_contain_text(f"Listing documents in {ALPHA}/nope")
+    expect(lines.nth(1)).to_contain_text(f"Listing documents in {ALPHA}")
+
+    frames = _frames(page)
+    assert _tool_frames(frames) == [
+        {"type": "tool", "name": "ls", "argument": f"{ALPHA}/nope"},
+        {"type": "tool", "name": "ls", "argument": ALPHA},
+    ], _tool_frames(frames)
+    done = next(f for f in frames if f.get("type") == "done")
+    assert done["deflected"] is False, done
+    # The loop ended in ONE refusal + ONE correction: the final answer is
+    # the recovery's PARENT listing (not the round-cap, not an echo of
+    # the refusal) — the model self-corrected and got the tree level.
+    bubble = _last_brain(page).locator(".bubble")
+    for line in [SOURCE_HEADER, *SOURCE_LINES]:
+        expect(bubble).to_contain_text(line)
+
+    row = _query_log_rows()
+    assert len(row) == 1
+    assert row[0].deflected is False

tests/e2e/test_tool_path_teaching.py

@@ -13,11 +13,14 @@ Run in isolation (DB must be up: ``podman compose up -d db``):
 MOCK-ONLY suite: ``E2E_REAL_LLM=1`` is not supported — the gate is the
 deterministic LS-TEACH flow in ``tests/e2e/mock_llm.py``
 (``LS_TEACH_TRIGGER`` — "list the files in this directory" — + the
-HIGH prompt's ``<tools>`` section): the incident's misuse (``ls`` with
+HIGH prompt's ``<tools>`` section; phase 94: the drill-down ``ls`` —
-``{"path": "."}``, id ``call_0``) → the agent's teaching refusal
+the corrected no-arg listing carries sources only, so the flow drills
-(``No source named '.' — check the ls output. (…)``) → the corrected
+one level before the first file line exists): the incident's misuse
-no-arg ``ls()`` (id ``call_1``) → the deterministic
+(``ls`` with ``{"path": "."}``, id ``call_0``) → the agent's teaching
-``These are the indexed documents: <first catalog line>`` answer.
+refusal (``No source named '.' — check the ls output. (…)``) → the
+corrected no-arg ``ls()`` (id ``call_1``) → the drill ``ls`` scoped to
+the first source of the listing (id ``call_2``) → the deterministic
+``These are the indexed documents: <first file line>`` answer.
 
 KB fixture (TRUNCATE-then-seed, house pattern): ONE source with TWO
 documents of known ``source``/``path``/``title`` (catalog order =
@@ -39,21 +42,24 @@ documents of known ``source``/``path``/``title`` (catalog order =
 Test → phase mapping (Playwright Mapping Rule):
 1. ``test_ls_misuse_self_corrects_to_noarg_listing`` — the grounded
    LS-TEACH turn: the turn settles (composer re-enables, ``done``
-   observed), the answer bubble carries the first catalog line — the
+   observed), the answer bubble carries the first file line — the
    first document's ``source:`` / ``path:`` / title fields (the
-   catalog reached the model and landed in the answer), the UI shows
+   folder listing reached the model and landed in the answer), the UI
-   the two tool lines (``🔎 Listing documents in <code>.</code>``
+   shows the three tool lines (``🔎 Listing documents in
-   then ``🔎 Listing documents``), and no error banner. Wire level:
+   <code>.</code>``, ``🔎 Listing documents``, then the drill
-   the ``tool`` frames arrive in order — first ``ls`` with
+   ``🔎 Listing documents in <source>`` — phase 94), and no error
-   ``argument: "."``, then ``ls`` with ``argument: null`` — and there
+   banner. Wire level: the ``tool`` frames arrive in order — first
-   is NO third ``tool`` frame (the loop ended in one correction, not
+   ``ls`` with ``argument: "."``, then ``ls`` with ``argument: null``,
+   then the drill ``ls`` scoped to the source — and there is NO fourth
+   ``tool`` frame (the loop ended in one correction + one drill, not
    at the round cap).
 2. ``test_plain_tool_flow_not_swallowed_by_new_trigger`` — in the SAME
    session, the LS-TEACH turn settles and a follow-up question
    carrying ``TOOLS_TRIGGER`` (the single-read flow) still settles
-   with the read flow's answer (``ls`` → ``read`` on the first
+   with the read flow's answer (``ls`` → the drill ``ls`` (phase 94)
-   catalog line's combined identity → ``Read <source/path>. <quote>``)
+   → ``read`` on the first file line's combined identity →
-   — the new flow did not swallow the existing trigger.
+   ``Read <source/path>. <quote>``) — the new flow did not swallow
+   the existing trigger.
 """
 from __future__ import annotations
 
@@ -69,7 +75,7 @@ from sqlalchemy import text
 from sqlalchemy.orm import Session
 
 from app.db import SessionLocal
-from app.models import Chunk, Document
+from app.models import Chunk, Document, GitSource
 from e2e.auth_helpers import login
 from tests.e2e.mock_llm import (
     LS_TEACH_TRIGGER,
@@ -211,7 +217,14 @@ def _seed_fixture(db: Session) -> None:
     cosines well past the E2E 0.30 threshold and FTS-matches too →
     grounded). DOC2 is the seed context only — the single-read flow
     reads the catalog-FIRST document (DOC1), which is not in context.
+
+    Phase 94: the drill-down ``ls`` top level reads the registry —
+    register the source (TRUNCATEd in ``_reset_db_fixture``): the
+    corrected no-arg listing names it, and the drill scopes to it. A
+    non-empty table also ignores the operator's ``BOR_GIT_SOURCES``
+    fallback — deterministic.
     """
+    db.add(GitSource(url=SEED_SOURCE, kind="local"))
     db.add(
         Document(
             source=SEED_SOURCE,
@@ -255,7 +268,10 @@ def _reset_db_fixture() -> None:
     prompts, byte-stable answers."""
     with SessionLocal() as db:
         db.execute(
-            text("TRUNCATE chunks, documents, query_log, steering_notes, kb_overview")
+            text(
+                "TRUNCATE chunks, documents, query_log, steering_notes, "
+                "kb_overview, git_sources"
+            )
         )
         db.commit()
         _seed_fixture(db)
@@ -382,24 +398,30 @@ def test_ls_misuse_self_corrects_to_noarg_listing(
     expect(bubble).to_contain_text(FIRST_CATALOG_LINE)
     _assert_no_error_banner(page)
 
-    # The UI shows the two tool lines in order: the scoped misuse
+    # The UI shows the three tool lines in order: the scoped misuse
-    # (🔎 Listing documents in <code>.</code>) then the corrected
+    # (🔎 Listing documents in <code>.</code>), the corrected
-    # unscoped listing (🔎 Listing documents — no <code>).
+    # unscoped listing (🔎 Listing documents — no <code>), then the
+    # drill (🔎 Listing documents in <source> — phase 94, the top
+    # level lists sources only, so the file lines need one more level).
     lines = page.locator(".msg.brain .tool-call")
-    expect(lines).to_have_count(2)
+    expect(lines).to_have_count(3)
     expect(lines.nth(0)).to_contain_text("Listing documents in")
     expect(lines.nth(0).locator("code")).to_have_text(".")
     expect(lines.nth(1)).to_contain_text("Listing documents")
     expect(lines.nth(1).locator("code")).to_have_count(0)
+    expect(lines.nth(2)).to_contain_text("Listing documents in")
+    expect(lines.nth(2).locator("code")).to_have_text(SEED_SOURCE)
 
-    # Two rounds on the wire: the tool frames arrive in order — first
+    # Three rounds on the wire: the tool frames arrive in order —
-    # ls with argument "." (the incident's misuse), then ls with
+    # first ls with argument "." (the incident's misuse), then ls with
-    # argument null (the correction) — and there is NO third tool
+    # argument null (the correction), then the drill ls scoped to the
-    # frame: the loop ended in one correction, not at the round cap.
+    # source (phase 94) — and there is NO fourth tool frame: the loop
+    # ended in one correction + one drill, not at the round cap.
     frames = _drain_frames(page)
     assert _tool_frames(frames) == [
         {"type": "tool", "name": "ls", "argument": "."},
         {"type": "tool", "name": "ls", "argument": None},
+        {"type": "tool", "name": "ls", "argument": SEED_SOURCE},
     ]
     first_delta = next(i for i, f in enumerate(frames) if f.get("type") == "delta")
     assert all(
@@ -433,6 +455,7 @@ def test_plain_tool_flow_not_swallowed_by_new_trigger(
     assert _tool_frames(teach_frames) == [
         {"type": "tool", "name": "ls", "argument": "."},
         {"type": "tool", "name": "ls", "argument": None},
+        {"type": "tool", "name": "ls", "argument": SEED_SOURCE},
     ]
     expect(
         page.locator(".msg.brain .bubble").last
@@ -445,14 +468,17 @@ def test_plain_tool_flow_not_swallowed_by_new_trigger(
     _wait_settled(page)
 
     second_msg = page.locator(".msg.brain").last
-    # The UI shows the single-read flow's two lines: the unscoped ls
+    # The UI shows the single-read flow's three lines: the unscoped ls,
-    # then the read of the first catalog line's COMBINED identity.
+    # the drill ls (phase 94), then the read of the first file line's
+    # COMBINED identity.
     lines = second_msg.locator(".tool-call")
-    expect(lines).to_have_count(2)
+    expect(lines).to_have_count(3)
     expect(lines.nth(0)).to_contain_text("Listing documents")
     expect(lines.nth(0).locator("code")).to_have_count(0)
-    expect(lines.nth(1)).to_contain_text("Reading ")
+    expect(lines.nth(1)).to_contain_text("Listing documents in")
-    expect(lines.nth(1).locator("code")).to_have_text(DOC1_SP)
+    expect(lines.nth(1).locator("code")).to_have_text(SEED_SOURCE)
+    expect(lines.nth(2)).to_contain_text("Reading ")
+    expect(lines.nth(2).locator("code")).to_have_text(DOC1_SP)
 
     # The answer quotes the read document (the mock's deterministic
     # echo: "Read <source/path>. <first 80 chars>").
@@ -461,11 +487,13 @@ def test_plain_tool_flow_not_swallowed_by_new_trigger(
     expect(bubble).to_contain_text(READ_ANSWER_QUOTE)
     _assert_no_error_banner(page)
 
-    # Wire level for the follow-up: ls (null) → read (the combined
+    # Wire level for the follow-up: ls (null) → the drill ls (the
-    # identity) — the single-read flow, unchanged.
+    # source, phase 94) → read (the combined identity) — the
+    # single-read flow, grown by the drill step.
     frames = _drain_frames(page)
     assert _tool_frames(frames) == [
         {"type": "tool", "name": "ls", "argument": None},
+        {"type": "tool", "name": "ls", "argument": SEED_SOURCE},
         {"type": "tool", "name": "read", "argument": DOC1_SP},
     ]
     done = next(f for f in frames if f.get("type") == "done")

tests/integration/test_agent_tools.py

@@ -1,19 +1,28 @@
 """Integration: the agent DB accessors against real Postgres (phase 37;
-the harness-aligned ``ls``/``read``/``grep`` surface, phase 70).
+the harness-aligned ``ls``/``read``/``grep`` surface, phase 70; the
+drill-down tree ``ls``, phase 94).
 
-``list_catalog`` must order rows by ``(source, path)`` — the same order
+``_source_document_rows`` must order a source's rows by ``path`` (the
-as ``GET /api/docs`` — ``list_source_names`` must resolve the
+file lines' catalog order), ``list_source_names`` must resolve the
-registered source names (the scoped ``ls`` join), and ``find_document``
+registered source names (the registry join), and ``find_document``
 must resolve a hit to the full document row (content included, for the
 never-truncated read) and return ``None`` for unknown pairs. Phase 70:
 the ``ls``/``read``/``grep`` tools are pinned here too — the locked
 parameter shape in ``AGENT_TOOLS``, and scripted ``ToolCallPiece``s
-executed through ``run_agent`` against the real DB: ``ls`` scoped to a
+executed through ``run_agent`` against the real DB. Phase 94: the
-registered source name (unknown name → refusal), ``read`` on the
+drill-down ``ls`` against the REAL tables — ``ls()`` lists the
-canonical combined ``source/path`` form (first-slash split; a bare
+registered sources (registry order, recursive counts, stored
-source name and an unknown identity get the no-document refusal), and
+source-root summaries from ``folder_summaries``), ``ls(source)`` /
-``grep`` (``all_documents`` for a whole-KB search, ``find_document`` for
+``ls(source/folder)`` list one folder level (the SQL prefix logic:
-a scoped one).
+subfolders = slash-boundary prefixes, counts = the recursive subtree,
+file lines in catalog order, capped at 50 + the grep-pointer note),
+and the refusals (unknown source segment → the no-source refusal; an
+unknown folder → NOT-A_FOLDER with the parent's subfolders).
+``read`` runs on the canonical combined ``source/path`` form
+(first-slash split; a bare source name and an unknown identity get the
+no-document refusal), and ``grep`` (``all_documents`` for a whole-KB
+search, ``find_document`` for a scoped one) — both byte-identical
+across the phase-94 change.
 
 Requires:  podman compose up -d db
 """
@@ -30,7 +39,7 @@ from sqlalchemy import delete, text
 from sqlalchemy.orm import Session
 
 from app.config import Settings
-from app.models import Document, GitSource
+from app.models import Document, FolderSummary, GitSource
 from app.rag import agent
 from app.rag.agent import AGENT_TOOLS, AgentHolder, run_agent
 from app.rag.llm import LLMClient, RetryPiece, StreamPiece, ToolCallPiece
@@ -55,11 +64,30 @@ def _doc(db: Session, source: str, path: str, title: str, content: str) -> Docum
 
 @pytest.fixture()
 def kb(db) -> Iterator[None]:
-    """Fresh documents table (chunks first — the FK) for these accessors."""
+    """Fresh documents + folder_summaries tables (chunks first — the FK)
-    db.execute(text("TRUNCATE chunks, documents"))
+    for these accessors (phase 94: the drill-down ``ls`` reads the
+    stored summaries too)."""
+    db.execute(text("TRUNCATE chunks, documents, folder_summaries"))
     db.commit()
     yield
-    db.execute(text("TRUNCATE chunks, documents"))
+    db.execute(text("TRUNCATE chunks, documents, folder_summaries"))
+    db.commit()
+
+
+@pytest.fixture()
+def registry(db) -> Iterator[None]:
+    """A FRESH two-source registry (phase 94): the drill-down ``ls``
+    top level IS the registry, so the table is truncated and re-seeded
+    around the tests in a controlled ``(added_at, id)`` order —
+    ``Deployments`` before ``Homelab`` (the top-level listing order)."""
+    db.execute(text("TRUNCATE git_sources"))
+    db.commit()
+    db.add(GitSource(url="https://github.com/reese/Deployments.git", kind="git"))
+    db.commit()
+    db.add(GitSource(url="https://github.com/reese/Homelab.git", kind="git"))
+    db.commit()
+    yield
+    db.execute(text("TRUNCATE git_sources"))
     db.commit()
 
 
@@ -76,21 +104,24 @@ def src(db) -> Iterator[GitSource]:
     db.commit()
 
 
-def test_list_catalog_orders_by_source_then_path(kb, db) -> None:
+def test_source_document_rows_order_by_path_within_the_source(kb, db) -> None:
+    """Phase 94: the file lines' order — the source's rows in ``path``
+    order (the old ``list_catalog``'s per-source ordering, now the
+    ``ls`` folder-level accessor's contract; a different source's rows
+    never leak in)."""
     _doc(db, "Zeta", "b/second.md", "Zeta B", "ZB")
     _doc(db, "Zeta", "a/first.md", "Zeta A", "ZA")
     _doc(db, "Alpha", "c/third.md", "Alpha C", "AC")
     db.commit()
 
-    assert agent.list_catalog(db) == [
+    assert agent._source_document_rows(db, "Zeta") == [
-        ("Alpha", "c/third.md", "Alpha C"),
+        ("a/first.md", "Zeta A"),
-        ("Zeta", "a/first.md", "Zeta A"),
+        ("b/second.md", "Zeta B"),
-        ("Zeta", "b/second.md", "Zeta B"),
     ]
 
 
-def test_list_catalog_is_empty_without_rows(kb, db) -> None:
+def test_source_document_rows_is_empty_without_rows(kb, db) -> None:
-    assert agent.list_catalog(db) == []
+    assert agent._source_document_rows(db, "Zeta") == []
 
 
 def test_list_source_names_resolves_registry_rows(db) -> None:
@@ -238,30 +269,156 @@ async def _consume(
     return out
 
 
-# ---------- ls (scoped through the real registry) ----------
+# ---------- ls (the drill-down tree, phase 94 — the real registry + DB) ----------
 
 
-def test_ls_scoped_to_registered_source_through_run_agent(kb, src, db) -> None:
+def test_ls_top_level_lists_registered_sources_through_run_agent(
-    _doc(db, "Homelab", "a.md", "A", "A-CONTENT")
+    kb, registry, db
-    _doc(db, "Other", "b.md", "B", "B-CONTENT")
+) -> None:
+    """No path: the TOP level against the real tables — registry order
+    (``(added_at, id)`` — Deployments before Homelab), recursive counts
+    (all of a source's documents), the stored source-root summary
+    (``folder_path = ''``) shown only when stored."""
+    _doc(db, "Deployments", "a/one.md", "A1", "A1-CONTENT")
+    _doc(db, "Homelab", "x.md", "X", "X-CONTENT")
+    _doc(db, "Homelab", "y/z.md", "Z", "Z-CONTENT")
+    db.add(FolderSummary(source="Homelab", folder_path="", summary="Home lab notes."))
     db.commit()
 
-    holder, llm = _run_call(db, "ls", {"path": "Homelab"})
+    holder, llm = _run_call(db, "ls", {})
 
-    # Offered: the first request carries AGENT_TOOLS (the 3-tool list).
     assert llm.requests[0][1] == AGENT_TOOLS
-    # Executed against the real DB: the listing filtered to the source.
     assert llm.requests[1][0][3]["content"] == (
-        "1 documents:\nsource: Homelab | path: a.md | title: A"
+        "2 sources:\n"
+        "\n"
+        "Deployments — 1 documents\n"
+        "Homelab — 2 documents\n"
+        "  Home lab notes."
     )
     assert holder.tool_calls == 1
     assert holder.read_docs == []
 
 
+def test_ls_top_level_empty_registry_through_run_agent(
+    kb, db, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """No registered sources: the top level is the header line alone
+    (``0 sources:`` — the old ``0 documents:`` behavior preserved in
+    spirit), still counted. The env fallback (``BOR_GIT_SOURCES`` — the
+    operator's ``.env`` may name sources) is emptied for the test, so
+    the registry is genuinely empty."""
+    import app.rag.git_sources as git_sources_mod
+
+    db.execute(text("TRUNCATE git_sources"))
+    db.commit()
+    monkeypatch.setattr(
+        git_sources_mod,
+        "get_settings",
+        lambda: _settings(git_sources=""),
+    )
+    _doc(db, "Orphan", "a.md", "A", "A-CONTENT")  # indexed but unregistered
+    db.commit()
+
+    holder, llm = _run_call(db, "ls", {})
+    assert llm.requests[1][0][3]["content"] == "0 sources:"
+    assert holder.tool_calls == 1
+
+
+def test_ls_source_scope_lists_root_folder_through_run_agent(kb, registry, db) -> None:
+    """A registered source name: the source's ROOT folder — the direct
+    subfolders (path order, recursive counts, stored summaries attached)
+    + the root's own file lines in catalog order — against the real
+    tables; a registered source with no documents lists its header
+    line alone."""
+    _doc(db, "Homelab", "backups/cron.md", "Cron", "CRON")
+    _doc(db, "Homelab", "backups/restic.md", "Restic", "RESTIC")
+    _doc(db, "Homelab", "networking/lan.md", "LAN", "LAN")
+    _doc(db, "Homelab", "readme.md", "Readme", "README")
+    db.add(
+        FolderSummary(
+            source="Homelab", folder_path="backups", summary="Backup notes."
+        )
+    )
+    db.commit()
+
+    holder, llm = _run_call(db, "ls", {"path": "Homelab"})
+
+    assert llm.requests[1][0][3]["content"] == (
+        "Homelab — 1 documents, 2 folders:\n"
+        "\n"
+        "  backups/ — 2 documents: Backup notes.\n"
+        "  networking/ — 1 documents\n"
+        "\n"
+        "source: Homelab | path: readme.md | title: Readme"
+    )
+    assert holder.tool_calls == 1
+    assert holder.read_docs == []
+
+    # A registered source with no documents: the header line alone.
+    holder0, llm0 = _run_call(db, "ls", {"path": "Deployments"})
+    assert llm0.requests[1][0][3]["content"] == "Deployments — 0 documents, 0 folders:"
+    assert holder0.tool_calls == 1
+
+
+def test_ls_nested_folder_scope_drills_one_level_through_run_agent(
+    kb, registry, db
+) -> None:
+    """A ``source/folder`` path: that folder's subfolders + own file
+    lines (identity = ``source/folder``) — the drill-down against the
+    real tables."""
+    _doc(db, "Homelab", "networking/lan/a.md", "A", "A")
+    _doc(db, "Homelab", "networking/lan/b.md", "B", "B")
+    _doc(db, "Homelab", "networking/vpn/c.md", "C", "C")
+    db.commit()
+
+    holder, llm = _run_call(db, "ls", {"path": "Homelab/networking"})
+
+    assert llm.requests[1][0][3]["content"] == (
+        "Homelab/networking — 0 documents, 2 folders:\n"
+        "\n"
+        "  networking/lan/ — 2 documents\n"
+        "  networking/vpn/ — 1 documents"
+    )
+    assert holder.tool_calls == 1
+    assert holder.read_docs == []
+
+    # One level deeper.
+    holder2, llm2 = _run_call(db, "ls", {"path": "Homelab/networking/lan"})
+    assert llm2.requests[1][0][3]["content"] == (
+        "Homelab/networking/lan — 2 documents, 0 folders:\n"
+        "\n"
+        "source: Homelab | path: networking/lan/a.md | title: A\n"
+        "source: Homelab | path: networking/lan/b.md | title: B"
+    )
+    assert holder2.tool_calls == 1
+
+
+def test_ls_folder_file_cap_through_run_agent(kb, registry, db) -> None:
+    """The cap end-to-end: 51 direct files in one folder cost 50 file
+    lines + the deterministic grep-pointer note, never 51."""
+    for i in range(51):
+        _doc(db, "Homelab", f"big/f{i:03d}.md", f"T{i}", "BODY")
+    db.commit()
+
+    holder, llm = _run_call(db, "ls", {"path": "Homelab/big"})
+
+    content = llm.requests[1][0][3]["content"]
+    lines = content.splitlines()
+    assert lines[0] == "Homelab/big — 51 documents, 0 folders:"
+    assert lines[2] == "source: Homelab | path: big/f000.md | title: T0"
+    assert lines[51] == "source: Homelab | path: big/f049.md | title: T49"
+    assert lines[52] == (
+        "…and 1 more documents in this folder — use grep (pattern) to "
+        "find a specific one."
+    )
+    assert len(lines) == 53
+    assert holder.tool_calls == 1
+
+
 def test_ls_scoped_unknown_source_refused_through_run_agent(kb, src, db) -> None:
-    """Phase 72: the no-source refusal now carries the teaching
+    """A ``path`` without ``/`` matching no source name is a refusal —
-    parenthetical — the prefix byte-identical to the pre-phase-72 line;
+    the extended line with the teaching parenthetical (phase 72, the
-    still not counted."""
+    prefix byte-identical to the pre-phase-72 line); still not counted."""
     _doc(db, "Homelab", "a.md", "A", "A-CONTENT")
     db.commit()
 
@@ -274,11 +431,11 @@ def test_ls_scoped_unknown_source_refused_through_run_agent(kb, src, db) -> None
     assert holder.tool_calls == 0 and holder.read_docs == []
 
 
-def test_ls_path_like_scope_teaching_refusal_through_run_agent(kb, src, db) -> None:
+def test_ls_path_like_scope_unknown_source_gets_no_source_refusal(kb, src, db) -> None:
-    """Phase 72: a ``/``-containing ``path`` is a document path, not a
+    """Phase 94: a ``/`` now names a folder — the phase-72 document-path
-    source name — the ``LS_PATH_NOT_A_SOURCE`` teaching line (no
+    teaching is DELETED; a ``source/…`` argument whose FIRST segment
-    registry lookup needed), not counted, the tools stay offered on the
+    names no registered source gets the no-source refusal (the segment
-    next request."""
+    echoed), not counted, the tools stay offered."""
     _doc(db, "Homelab", "a.md", "A", "A-CONTENT")
     db.commit()
 
@@ -286,7 +443,30 @@ def test_ls_path_like_scope_teaching_refusal_through_run_agent(kb, src, db) -> N
 
     assert (
         llm.requests[1][0][3]["content"]
-        == agent.LS_PATH_NOT_A_SOURCE.format(path="app/rag/importer.py")
+        == agent.NO_SOURCE_NOT_A_DIRECTORY.format(scope="app")
+    )
+    assert holder.tool_calls == 0 and holder.read_docs == []
+    assert llm.requests[1][1] == AGENT_TOOLS  # rejected → tools stay offered
+
+
+def test_ls_unknown_folder_gets_not_a_folder_with_parents_subfolders(
+    kb, src, db,
+) -> None:
+    """Phase 94: a folder segment matching no indexed prefix gets the
+    NOT-A_FOLDER teaching — the argument echoed, the source named, its
+    DIRECT subfolders listed (the self-correction list), not counted,
+    the tools stay offered."""
+    _doc(db, "Homelab", "backups/cron.md", "Cron", "CRON")
+    _doc(db, "Homelab", "containers/caddy.md", "Caddy", "CADDY")
+    _doc(db, "Homelab", "networking/lan.md", "LAN", "LAN")
+    _doc(db, "Homelab", "readme.md", "Readme", "README")
+    db.commit()
+
+    holder, llm = _run_call(db, "ls", {"path": "Homelab/netwoking"})
+
+    assert llm.requests[1][0][3]["content"] == (
+        "'Homelab/netwoking' is not a folder — Homelab has: "
+        "backups/ containers/ networking/"
     )
     assert holder.tool_calls == 0 and holder.read_docs == []
     assert llm.requests[1][1] == AGENT_TOOLS  # rejected → tools stay offered

tests/integration/test_chat_api.py

@@ -943,7 +943,10 @@ def test_tool_execution_db_failure_yields_error_event(
     def boom(*_a: Any, **_k: Any) -> Any:
         raise RuntimeError("db exploded mid tool call")
 
-    monkeypatch.setattr(agent, "list_catalog", boom)
+    # Phase 94: the no-arg ``ls`` executes through ``ls_top`` — the
+    # failure hook moves with the rewrite (same contract: the tool
+    # frame goes out first, the structured error ends the turn).
+    monkeypatch.setattr(agent, "ls_top", boom)
     fastapi_app.dependency_overrides[chat_api.get_llm] = lambda: scripted
     try:
         _, _, frames = _stream_chat(client, QUESTION)

tests/integration/test_import_docs_git.py

@@ -104,6 +104,21 @@ def _stub_bump(monkeypatch: pytest.MonkeyPatch) -> list[None]:
     return bumps
 
 
+def _stub_folder_summaries(monkeypatch: pytest.MonkeyPatch) -> list[dict]:
+    """Stub the phase-94 folder-summary regeneration (this file keeps
+    its no-real-DB / no-network style — the real generator would read
+    the global ``documents`` table and burn ``lite`` calls). Returns
+    the call record; the canned stats are the zero dict."""
+    calls: list[dict] = []
+
+    async def fake_generate(db: object, llm: object, *, skip: bool = False) -> dict[str, int]:
+        calls.append({"skip": skip})
+        return {"generated": 0, "failed": 0, "pruned": 0}
+
+    monkeypatch.setattr(import_docs, "generate_folder_summaries", fake_generate)
+    return calls
+
+
 # --- repo_name -------------------------------------------------------------
 
 
@@ -293,6 +308,7 @@ def test_main_rows_branch_passes_ignore_map_to_import(
     fake_import = FakeImportSources()
     monkeypatch.setattr(import_docs, "import_sources", fake_import)
     _stub_bump(monkeypatch)
+    _stub_folder_summaries(monkeypatch)
 
     rc = import_docs.main([])
 
@@ -329,6 +345,7 @@ def test_main_git_sources_clone_then_import(
     fake_import = FakeImportSources()
     monkeypatch.setattr(import_docs, "import_sources", fake_import)
     bumps = _stub_bump(monkeypatch)
+    _stub_folder_summaries(monkeypatch)
 
     rc = import_docs.main([])
 
@@ -371,6 +388,7 @@ def test_main_cli_source_still_imports_manual_dir(
     fake_import = FakeImportSources()
     monkeypatch.setattr(import_docs, "import_sources", fake_import)
     bumps = _stub_bump(monkeypatch)
+    _stub_folder_summaries(monkeypatch)
 
     rc = import_docs.main(["--source", str(manual)])
 

tests/integration/test_import_docs_overview.py

@@ -23,6 +23,15 @@ and unchanged re-runs never bump (``sources_version=skipped``), and a
 failed ``lite`` never rolls the bump back. The counter is pinned to the
 migration-0010 seed (0) around every test by
 :func:`_reset_sources_version`.
+
+Phase 94 (task 02, line-extension house rule): the summary line now
+ends with the folder-summary stats —
+``folder_summaries=<generated>/<failed>/<pruned>`` when the gate fired
+(this fixture's 2-doc source holds exactly ONE qualifying subtree: the
+source root) or ``folder_summaries=skipped`` otherwise — so the line
+pinned here gains that token, and a KB-changing run burns exactly ONE
+extra ``lite`` call (the source-root folder summary, markdown files
+never get a document summary).
 """
 from __future__ import annotations
 
@@ -98,10 +107,10 @@ def src(tmp_path: Path) -> Path:
 
 @pytest.fixture(autouse=True)
 def _clean_kb(db: Session) -> Iterator[None]:
-    db.execute(text("TRUNCATE chunks, documents, kb_overview"))
+    db.execute(text("TRUNCATE chunks, documents, kb_overview, folder_summaries"))
     db.commit()
     yield
-    db.execute(text("TRUNCATE chunks, documents, kb_overview"))
+    db.execute(text("TRUNCATE chunks, documents, kb_overview, folder_summaries"))
     db.commit()
 
 
@@ -149,16 +158,24 @@ def test_changed_import_writes_overview_row(
 
     assert rc == 0
     assert "added=2" in out
-    assert out.rstrip().endswith("overview=updated sources_version=1")
+    # Phase 94: the line gains the folder-stats token — the 2-doc source
+    # holds one qualifying subtree (the source root): 1 generated.
+    assert out.rstrip().endswith(
+        "overview=updated sources_version=1 folder_summaries=1/0/0"
+    )
     assert _version(db) == 1  # phase 53: a changed import bumps exactly once
-    # Exactly one lite call — the overview itself (markdown files never
+    # Exactly two lite calls — the overview + the source-root folder
-    # get a summary, so nothing else may touch ``chat``).
+    # summary (markdown files never get a document summary, so nothing
-    assert len(llm.chat_calls) == 1
+    # else may touch ``chat``).
+    assert len(llm.chat_calls) == 2
     by_role = {m["role"]: m["content"] for m in llm.chat_calls[0]}
     assert "KB_OVERVIEW_MODE" in by_role["system"]
     # One line per doc: source — path — title (no summary for markdown).
     assert "MyDocs — alpha.md — Alpha" in by_role["user"]
     assert "MyDocs — beta.md — Beta" in by_role["user"]
+    by_role = {m["role"]: m["content"] for m in llm.chat_calls[1]}
+    assert "FOLDER_SUMMARY_MODE" in by_role["system"]
+    assert by_role["user"].splitlines()[0] == "Folder: MyDocs"
     # The model's outline lands in the single row.
     row = _row(db)
     assert row is not None
@@ -177,16 +194,20 @@ def test_unchanged_reimport_does_not_call_lite(
     llm = FakeEmbedder()
     rc, out = _run_main(monkeypatch, llm, ["--source", str(src)], capsys)
     assert rc == 0
-    assert out.rstrip().endswith("overview=updated sources_version=1")
+    assert out.rstrip().endswith(
-    assert len(llm.chat_calls) == 1
+        "overview=updated sources_version=1 folder_summaries=1/0/0"
+    )
+    assert len(llm.chat_calls) == 2  # overview + source-root folder summary
     assert _row(db) is not None
 
     # Same hashes → no KB change → no lite call, previous outline kept.
     rc, out = _run_main(monkeypatch, llm, ["--source", str(src)], capsys)
     assert rc == 0
     assert "unchanged=2" in out
-    assert out.rstrip().endswith("overview=skipped sources_version=skipped")
+    assert out.rstrip().endswith(
-    assert len(llm.chat_calls) == 1  # no new lite call
+        "overview=skipped sources_version=skipped folder_summaries=skipped"
+    )
+    assert len(llm.chat_calls) == 2  # no new lite call
     row = _row(db)
     assert row is not None and row.content == "Summary of MyDocs"
     assert _version(db) == 1  # phase 53: an unchanged re-run never bumps
@@ -201,7 +222,9 @@ def test_lite_failure_is_fail_soft(
     good = FakeEmbedder()
     rc, out = _run_main(monkeypatch, good, ["--source", str(src)], capsys)
     assert rc == 0
-    assert out.rstrip().endswith("overview=updated sources_version=1")
+    assert out.rstrip().endswith(
+        "overview=updated sources_version=1 folder_summaries=1/0/0"
+    )
     previous = _row(db)
     assert previous is not None
     previous_content = previous.content
@@ -213,8 +236,12 @@ def test_lite_failure_is_fail_soft(
     rc, out = _run_main(monkeypatch, bad, ["--source", str(src)], capsys)
     assert rc == 0  # a failed outline must not fail the import
     assert "updated=1" in out
-    assert out.rstrip().endswith("overview=failed sources_version=2")
+    # Phase 94: the folder batch fails too (per-folder fail-soft) — the
-    assert len(bad.chat_calls) == 1  # the (failed) attempt was made
+    # failed attempt counts into the stats, the previous row stays.
+    assert out.rstrip().endswith(
+        "overview=failed sources_version=2 folder_summaries=0/1/0"
+    )
+    assert len(bad.chat_calls) == 2  # the (failed) attempts were made
     row = _row(db)
     assert row is not None
     assert row.content == previous_content  # previous row untouched
@@ -232,8 +259,10 @@ def test_limit_run_skips_overview(
     llm = FakeEmbedder()
     rc, out = _run_main(monkeypatch, llm, ["--source", str(src)], capsys)
     assert rc == 0
-    assert out.rstrip().endswith("overview=updated sources_version=1")
+    assert out.rstrip().endswith(
-    assert len(llm.chat_calls) == 1
+        "overview=updated sources_version=1 folder_summaries=1/0/0"
+    )
+    assert len(llm.chat_calls) == 2
 
     # An incomplete walk must not rewrite the outline (mirrors the
     # --prune-with---limit guard) — and must not advance the version.
@@ -241,8 +270,10 @@ def test_limit_run_skips_overview(
     rc, out = _run_main(monkeypatch, llm, ["--source", str(src), "--limit", "1"], capsys)
     assert rc == 0
     assert "updated=1" in out
-    assert out.rstrip().endswith("overview=skipped sources_version=skipped")
+    assert out.rstrip().endswith(
-    assert len(llm.chat_calls) == 1  # --limit never burns a lite call
+        "overview=skipped sources_version=skipped folder_summaries=skipped"
+    )
+    assert len(llm.chat_calls) == 2  # --limit never burns a lite call
     row = _row(db)
     assert row is not None and row.content == "Summary of MyDocs"
     assert _version(db) == 1  # phase 53: --limit debug runs never bump
@@ -262,7 +293,9 @@ def test_empty_source_without_row_creates_nothing(
 
     assert rc == 0
     assert "files=0" in out
-    assert out.rstrip().endswith("overview=skipped sources_version=skipped")
+    assert out.rstrip().endswith(
+        "overview=skipped sources_version=skipped folder_summaries=skipped"
+    )
     assert llm.chat_calls == []  # no KB → no outline, no wasted model call
     assert _row(db) is None  # nothing created
     assert _version(db) == 0  # nothing changed → nothing bumped
@@ -283,7 +316,9 @@ def test_prune_only_run_bumps_sources_version(
     rc, out = _run_main(monkeypatch, llm, ["--source", str(src)], capsys)
     assert rc == 0
     assert "added=2" in out
-    assert out.rstrip().endswith("overview=updated sources_version=1")
+    assert out.rstrip().endswith(
+        "overview=updated sources_version=1 folder_summaries=1/0/0"
+    )
     assert _version(db) == 1
 
     # Delete one file; a --prune run drops exactly it: no add/update,
@@ -292,6 +327,12 @@ def test_prune_only_run_bumps_sources_version(
     rc, out = _run_main(monkeypatch, llm, ["--source", str(src), "--prune"], capsys)
     assert rc == 0
     assert "pruned=1" in out
-    assert out.rstrip().endswith("overview=skipped sources_version=2")
+    # Phase 94: the folder gate is the overview's (added + updated > 0
+    # or empty table) — a prune-only re-walk with a populated table
+    # skips generation (the remaining 1-doc source stays summarized by
+    # its existing root row, which still describes it).
+    assert out.rstrip().endswith(
+        "overview=skipped sources_version=2 folder_summaries=skipped"
+    )
     assert _version(db) == 2  # the prune-only change bumped exactly once
     assert _row(db) is not None  # the outline row is untouched

tests/integration/test_migration_0017.py

@@ -0,0 +1,248 @@
+"""Integration: migration 0017 (folder_summaries) schema contract
+(phase 94, task 01).
+
+Drives the **real Alembic engine** against the live dev database
+(``podman compose up -d db``), mirroring the house pattern of
+``test_migration_0016.py`` (information_schema assertions on the state
+the migration must leave). The tests target the 0016 → 0017 step
+explicitly so later migrations cannot break them:
+
+* upgrade 0016 → 0017 → the ``folder_summaries`` table exists with the
+  full column contract — PK ``(source, folder_path)`` (VARCHAR(120) /
+  VARCHAR(1000) NOT NULL, mirroring ``documents.source`` /
+  ``documents.path``), ``summary`` TEXT NOT NULL, ``updated_at``
+  TIMESTAMPTZ NOT NULL with the now() server default (house style) —
+  while the 0016 ``ui_settings`` schema survives;
+* inserted rows round-trip their values (a source-root row with
+  ``folder_path = ''`` and a nested-folder row);
+* downgrade to 0016 → the table is GONE (A13 — reversible), the rest of
+  the schema (``ui_settings`` + ``api_tokens``) survives;
+* upgrade back to 0017 → the table is back (round-trip).
+
+The ``alembic`` fixture guarantees the DB ends at head even if a test
+fails or the process is interrupted.
+"""
+from __future__ import annotations
+
+from collections.abc import Iterator
+from typing import Any
+
+import pytest
+from alembic.config import Config
+from sqlalchemy import text
+from sqlalchemy.exc import IntegrityError
+from sqlalchemy.orm import Session
+
+from alembic import command
+from app.db import db_available
+
+
+@pytest.fixture()
+def alembic(db: Session) -> Iterator[Config]:
+    """Real Alembic config bound to the dev DB (URL from app settings).
+
+    Starts at head (repairs an interrupted earlier run); teardown upgrades
+    to head no matter what happened, so the dev DB is never left below
+    head.
+    """
+    if not db_available():
+        pytest.skip("Postgres not reachable — run `podman compose up -d db` first")
+    cfg = Config()  # no alembic.ini file — env.py gets the URL from app config
+    cfg.set_main_option("script_location", "alembic")
+    command.upgrade(cfg, "head")
+    try:
+        yield cfg
+    finally:
+        command.upgrade(cfg, "head")
+
+
+def _version(db: Session) -> str | None:
+    return db.execute(text("SELECT version_num FROM alembic_version")).scalar()
+
+
+def _table_exists(db: Session, table: str) -> bool:
+    return (
+        db.execute(
+            text("SELECT 1 FROM information_schema.tables WHERE table_name = :t"),
+            {"t": table},
+        ).scalar()
+        is not None
+    )
+
+
+def _column(db: Session, table: str, column: str) -> tuple[Any, ...] | None:
+    """(data_type, is_nullable, column_default, character_maximum_length)
+    for one table column."""
+    row = db.execute(
+        text(
+            "SELECT data_type, is_nullable, column_default, character_maximum_length"
+            " FROM information_schema.columns"
+            " WHERE table_name = :t AND column_name = :c"
+        ),
+        {"t": table, "c": column},
+    ).fetchone()
+    return tuple(row) if row is not None else None
+
+
+def _pk_columns(db: Session, table: str) -> list[str]:
+    """The table's PRIMARY KEY columns in ordinal position."""
+    rows = db.execute(
+        text(
+            "SELECT kcu.column_name"
+            " FROM information_schema.table_constraints tc"
+            " JOIN information_schema.key_column_usage kcu"
+            "   ON kcu.constraint_name = tc.constraint_name"
+            "  AND kcu.table_name = tc.table_name"
+            " WHERE tc.table_name = :t"
+            "   AND tc.constraint_type = 'PRIMARY KEY'"
+            " ORDER BY kcu.ordinal_position"
+        ),
+        {"t": table},
+    ).fetchall()
+    return [r[0] for r in rows]
+
+
+def _clear_rows(db: Session) -> None:
+    db.execute(text("DELETE FROM folder_summaries"))
+    db.commit()
+
+
+def test_upgrade_to_0017_creates_folder_summaries(db: Session, alembic: Config) -> None:
+    """Upgrade 0016 → 0017: the table exists with the full column
+    contract (PK ``(source, folder_path)`` mirroring
+    ``documents.source`` / ``documents.path``; TEXT summary NOT NULL;
+    TIMESTAMPTZ updated_at NOT NULL with the now() server default), and
+    the table is ABSENT at 0016 while the 0016 ``ui_settings`` schema
+    survives the upgrade."""
+    command.downgrade(alembic, "0016")  # start from the pre-0017 state
+    assert _version(db) == "0016"
+    assert not _table_exists(db, "folder_summaries"), (
+        "folder_summaries must be absent at 0016"
+    )
+
+    command.upgrade(alembic, "0017")
+    assert _version(db) == "0017", "alembic_version must be at 0017"
+    assert _table_exists(db, "folder_summaries"), "the table must exist at 0017"
+
+    source = _column(db, "folder_summaries", "source")
+    assert source is not None, "folder_summaries.source is missing"
+    assert source[0] == "character varying", "source must be VARCHAR"
+    assert source[1] == "NO", "source must be NOT NULL (PK part 1)"
+    assert source[2] is None, "source must have no server default"
+    assert source[3] == 120, "source must be String(120) — documents.source"
+
+    folder = _column(db, "folder_summaries", "folder_path")
+    assert folder is not None, "folder_summaries.folder_path is missing"
+    assert folder[0] == "character varying", "folder_path must be VARCHAR"
+    assert folder[1] == "NO", "folder_path must be NOT NULL (PK part 2)"
+    assert folder[2] is None, "folder_path must have no server default"
+    assert folder[3] == 1000, "folder_path must be String(1000) — documents.path"
+
+    summary = _column(db, "folder_summaries", "summary")
+    assert summary is not None, "folder_summaries.summary is missing"
+    assert summary[0] == "text", "summary must be TEXT"
+    assert summary[1] == "NO", "summary must be NOT NULL (never stored empty)"
+
+    updated = _column(db, "folder_summaries", "updated_at")
+    assert updated is not None, "folder_summaries.updated_at is missing"
+    assert updated[0] == "timestamp with time zone", "updated_at must be TIMESTAMPTZ"
+    assert updated[1] == "NO", "updated_at must be NOT NULL"
+    assert updated[2] is not None and "now" in str(updated[2]), (
+        "updated_at must carry the now() server default (house style)"
+    )
+
+    assert _pk_columns(db, "folder_summaries") == ["source", "folder_path"]
+
+    # The 0016 schema survives the additive upgrade.
+    semantic = _column(db, "ui_settings", "ok_bg")
+    assert semantic is not None and semantic[3] == 7, (
+        "ui_settings.ok_bg (0016) must survive the upgrade"
+    )
+
+
+def test_inserted_rows_round_trip(db: Session, alembic: Config) -> None:
+    """At 0017, a source-root row (``folder_path = ''``) and a nested
+    folder row round-trip their values, and the composite PK rejects a
+    duplicate (source, folder_path) pair."""
+    command.upgrade(alembic, "head")
+    try:
+        db.execute(
+            text(
+                "INSERT INTO folder_summaries (source, folder_path, summary)"
+                " VALUES ('Homelab', '', 'Root summary.')"
+            )
+        )
+        db.execute(
+            text(
+                "INSERT INTO folder_summaries (source, folder_path, summary)"
+                " VALUES ('Homelab', 'deployments/ansible', 'Ansible summary.')"
+            )
+        )
+        db.commit()
+        rows = db.execute(
+            text(
+                "SELECT source, folder_path, summary, updated_at"
+                " FROM folder_summaries ORDER BY folder_path"
+            )
+        ).fetchall()
+        assert len(rows) == 2, "both rows must be stored"
+        assert rows[0][0] == "Homelab" and rows[0][1] == "", (
+            "the source-root row uses folder_path = ''"
+        )
+        assert rows[0][2] == "Root summary.", "summary must round-trip verbatim"
+        assert rows[0][3] is not None, "updated_at must be stamped (server default)"
+        assert rows[1][1] == "deployments/ansible", (
+            "a nested folder path must round-trip verbatim"
+        )
+        assert rows[1][2] == "Ansible summary."
+
+        with pytest.raises(IntegrityError):
+            db.execute(
+                text(
+                    "INSERT INTO folder_summaries (source, folder_path, summary)"
+                    " VALUES ('Homelab', 'deployments/ansible', 'dup')"
+                )
+            )
+        db.rollback()  # the IntegrityError aborts the open transaction
+    finally:
+        _clear_rows(db)
+
+
+def test_downgrade_to_0016_drops_the_table(db: Session, alembic: Config) -> None:
+    """Downgrade 0017 → 0016: the table is gone (A13 — fully
+    reversible) while the rest of the schema survives (the 0016
+    ``ui_settings`` semantic columns, ``api_tokens``, ``documents``)."""
+    command.downgrade(alembic, "0016")
+    assert _version(db) == "0016"
+    assert not _table_exists(db, "folder_summaries"), (
+        "folder_summaries must be dropped"
+    )
+
+    semantic = _column(db, "ui_settings", "accent_line")
+    assert semantic is not None and semantic[3] == 7, (
+        "ui_settings.accent_line (0016) must survive the downgrade"
+    )
+    token_col = _column(db, "api_tokens", "token_hash")
+    assert token_col is not None and token_col[0] == "character varying", (
+        "api_tokens.token_hash must survive the downgrade"
+    )
+    doc_path = _column(db, "documents", "path")
+    assert doc_path is not None and doc_path[3] == 1000, (
+        "documents.path must survive the downgrade"
+    )
+
+
+def test_upgrade_round_trip_restores_the_table(db: Session, alembic: Config) -> None:
+    """Downgrade to 0016, then upgrade back to 0017: the table is back
+    with the column contract and PK intact."""
+    command.downgrade(alembic, "0016")
+    command.upgrade(alembic, "0017")
+    assert _version(db) == "0017", "round-trip upgrade must land at 0017"
+    assert _table_exists(db, "folder_summaries"), "the table must be back"
+
+    folder = _column(db, "folder_summaries", "folder_path")
+    assert folder is not None, "folder_summaries.folder_path must be back"
+    assert folder[0] == "character varying", "folder_path must be VARCHAR"
+    assert folder[1] == "NO", "folder_path must be NOT NULL after the round-trip"
+    assert folder[3] == 1000, "folder_path must be String(1000) after the round-trip"
+    assert _pk_columns(db, "folder_summaries") == ["source", "folder_path"]

tests/integration/test_sync_api.py

@@ -48,9 +48,16 @@ and every failure path (git error, model down) never bumps. The
 counter is pinned to the migration-0010 seed (0) around every test by
 :func:`_reset_sources_version`.
 
-The git / import / overview layers are monkeypatched in ``app.api.sync``
+The git / import / overview / folder-summary layers are monkeypatched
-(same fake style as ``test_import_docs_git.py``) — no real git, no LLM:
+in ``app.api.sync`` (same fake style as ``test_import_docs_git.py``) —
-the runner's state machine and HTTP surface are under test.
+no real git, no LLM: the runner's state machine and HTTP surface are
+under test. Phase 94 (task 02): the folder-summary layer gets the same
+treatment — the fake-import tests' canned summaries would otherwise
+steer the REAL ``generate_folder_summaries`` at the global
+``documents`` table and the real ``LLMClient`` (network); the
+real-import tests (host temp dirs, deterministic ``FakeEmbedder``) keep
+the real generator, with ``folder_summaries`` truncated around every
+test (:func:`_clean_folder_summaries`).
 
 The admin client is used **as a context manager** on purpose: the
 background sync task lives on the app's event loop, so the loop must
@@ -182,6 +189,19 @@ def clean_documents(db: Session) -> Iterator[None]:
     db.commit()
 
 
+@pytest.fixture(autouse=True)
+def _clean_folder_summaries(db: Session) -> Iterator[None]:
+    """Phase 94: the ``folder_summaries`` table is global state the real
+    generator (the real-import tests) writes — truncated around every
+    sync test so the change-gate / table-empty-gate assertions start
+    from a known (empty) table."""
+    db.execute(text("TRUNCATE folder_summaries"))
+    db.commit()
+    yield
+    db.execute(text("TRUNCATE folder_summaries"))
+    db.commit()
+
+
 def _real_llm(monkeypatch: pytest.MonkeyPatch) -> None:
     """The pipeline's ``LLMClient`` becomes the deterministic in-process
     ``FakeEmbedder`` (real import, no network). ``FakeEmbedder``
@@ -276,6 +296,34 @@ class FakeOverview:
         return self.ok
 
 
+class FakeFolderSummaries:
+    """Records every ``generate_folder_summaries`` call; canned stats.
+
+    Phase 94 (task 02): keeps the fake-import tests at the deterministic
+    layer boundary — the real generator would read the global
+    ``documents`` table and call the (real) ``LLMClient`` over the
+    network. The generator only flushes, so the fake honours the
+    ``skip`` flag the same way (the zero stats, no side effects)."""
+
+    ZERO = {"generated": 0, "failed": 0, "pruned": 0}
+
+    def __init__(self, stats: dict[str, int] | None = None) -> None:
+        self.stats = stats if stats is not None else dict(self.ZERO)
+        self.llms: list[LLMClient] = []
+        self.sessions: list[Session] = []
+        self.skip_flags: list[bool] = []
+
+    async def __call__(
+        self, db: Session, llm: LLMClient, *, skip: bool = False
+    ) -> dict[str, int]:
+        self.skip_flags.append(skip)
+        if skip:
+            return dict(self.ZERO)
+        self.llms.append(llm)
+        self.sessions.append(db)
+        return dict(self.stats)
+
+
 def _fake_clone() -> tuple[list[tuple[str, Path]], object]:
     """A ``clone_or_pull`` that materialises a checkout with one .md file."""
     calls: list[tuple[str, Path]] = []
@@ -327,6 +375,7 @@ def test_admin_sync_success_reports_full_detail(
     monkeypatch.setattr(sync_api, "import_sources", fake_import)
     fake_overview = FakeOverview(ok=True)
     monkeypatch.setattr(sync_api, "regenerate_overview", fake_overview)
+    monkeypatch.setattr(sync_api, "generate_folder_summaries", FakeFolderSummaries())
 
     _login(sync_client)
     assert sync_client.get("/api/sync/status").json() == {
@@ -399,6 +448,7 @@ def test_unchanged_kb_skips_overview_refresh(
     monkeypatch.setattr(sync_api, "import_sources", fake_import)
     fake_overview = FakeOverview(ok=True)
     monkeypatch.setattr(sync_api, "regenerate_overview", fake_overview)
+    monkeypatch.setattr(sync_api, "generate_folder_summaries", FakeFolderSummaries())
 
     _login(sync_client)
     assert sync_client.post("/api/sync").status_code == 202
@@ -435,6 +485,7 @@ def test_double_trigger_while_running_returns_409(
     fake_import = FakeImportSources(ImportSummary(files=1, added=1), delay=0.5)
     monkeypatch.setattr(sync_api, "import_sources", fake_import)
     monkeypatch.setattr(sync_api, "regenerate_overview", FakeOverview(ok=True))
+    monkeypatch.setattr(sync_api, "generate_folder_summaries", FakeFolderSummaries())
 
     _login(sync_client)
     assert sync_client.post("/api/sync").status_code == 202
@@ -551,12 +602,17 @@ def test_db_rows_win_over_env(
     fake_import = FakeImportSources(ImportSummary(files=1, added=1))
     monkeypatch.setattr(sync_api, "import_sources", fake_import)
     monkeypatch.setattr(sync_api, "regenerate_overview", FakeOverview(ok=True))
+    fake_folders = FakeFolderSummaries()
+    monkeypatch.setattr(sync_api, "generate_folder_summaries", fake_folders)
 
     _login(sync_client)
     with caplog.at_level(logging.INFO, logger="app.api.sync"):
         assert sync_client.post("/api/sync").status_code == 202
         body = _poll(sync_client, "success")
 
+    # Phase 94: the changed canned summary fired the (stubbed) folder
+    # step with the run's own session + the import's LLM client.
+    assert fake_folders.llms == [fake_import.llms[0]]
     assert clone_calls == [(db_url, tmp_path / "bor" / "managed")]
     assert fake_import.sources == [[tmp_path / "bor" / "managed"]]
     assert "env.example.com" not in str(body)  # the env URL never reaches the UI
@@ -584,6 +640,7 @@ def test_env_fallback_when_table_empty(
     fake_import = FakeImportSources(ImportSummary(files=1, added=1))
     monkeypatch.setattr(sync_api, "import_sources", fake_import)
     monkeypatch.setattr(sync_api, "regenerate_overview", FakeOverview(ok=True))
+    monkeypatch.setattr(sync_api, "generate_folder_summaries", FakeFolderSummaries())
 
     _login(sync_client)
     with caplog.at_level(logging.INFO, logger="app.api.sync"):
@@ -988,6 +1045,7 @@ def test_sync_builds_ignore_map_by_root_string_with_union(
     fake_import = FakeImportSources(ImportSummary(files=1, added=1))
     monkeypatch.setattr(sync_api, "import_sources", fake_import)
     monkeypatch.setattr(sync_api, "regenerate_overview", FakeOverview(ok=True))
+    monkeypatch.setattr(sync_api, "generate_folder_summaries", FakeFolderSummaries())
 
     _login(sync_client)
     assert sync_client.post("/api/sync").status_code == 202
@@ -1022,6 +1080,7 @@ def test_sync_without_ignore_lists_passes_empty_map(
     fake_import = FakeImportSources(ImportSummary(files=1, added=1))
     monkeypatch.setattr(sync_api, "import_sources", fake_import)
     monkeypatch.setattr(sync_api, "regenerate_overview", FakeOverview(ok=True))
+    monkeypatch.setattr(sync_api, "generate_folder_summaries", FakeFolderSummaries())
 
     _login(sync_client)
     assert sync_client.post("/api/sync").status_code == 202

tests/integration/test_sync_folder_summaries.py

@@ -0,0 +1,664 @@
+"""Integration: the sync-time folder-summary wiring (phase 94, task 02).
+
+Extends the KB-overview sync pattern (``test_import_docs_overview.py``
+is the template) to the phase-94 folder summaries — both sync paths
+regenerate ``folder_summaries`` change-gated (added + updated > 0) or
+on an empty table (the first full run after migration 0017 / a
+``--limit`` first walk), per-folder fail-soft, best-effort, and in the
+run's own short-lived session (the phase-53 flush-then-caller-commits
+convention — the generator only flushes, the sync path commits).
+
+Script path (``scripts.import_docs.main`` end to end, fake LLM, real
+DB, explicit ``--source``):
+
+- a KB-changing import → one row per ≥ 2-doc subtree (the source root
+  + the 2-doc folder; the 1-doc folder gets none), committed in the
+  run's transaction, the summary line ending
+  ``folder_summaries=<generated>/<failed>/<pruned>``;
+- an unchanged re-import → zero ``lite`` calls,
+  ``folder_summaries=skipped``, rows untouched;
+- a subtree dropping below 2 docs after a changed re-walk → its row
+  pruned;
+- one folder's ``lite`` failure → its previous row kept, the other
+  lands, exit code 0, stats ``1/1/0``;
+- a ``--limit`` debug run → no generation, no rows,
+  ``folder_summaries=skipped``;
+- a fresh (empty) table after a ``--limit`` first walk → an unchanged
+  full walk generates (the table-empty first-run trigger).
+
+API path (``POST /api/sync`` end to end, real import over a host temp
+local dir, deterministic ``FakeEmbedder``):
+
+- a KB-changing sync → the rows land (visible via the test's own
+  session) and the status detail keeps its exact pre-phase key set
+  (no folder-summary surface — the stats are log-only);
+- an unchanged re-sync → zero ``FOLDER_SUMMARY_MODE`` calls;
+- a ``lite`` outage (one folder failing) → the failed folder's row is
+  kept, the run reports ``success`` (never ``failed``), and the
+  sources-version bump still lands (the bump is change-gated on the
+  KB, not on the summaries);
+- an empty table after a populated sync (the migration-0017 scenario)
+  → an unchanged walk regenerates (the overview's API gate, purely
+  change-gated, does not).
+"""
+from __future__ import annotations
+
+import logging
+import time
+from collections.abc import Iterator
+from datetime import datetime
+from pathlib import Path
+
+import pytest
+from fastapi.testclient import TestClient
+from sqlalchemy import select, text
+from sqlalchemy.orm import Session
+
+from app.api import sync as sync_api
+from app.config import Settings
+from app.db import SessionLocal, db_available
+from app.main import app as fastapi_app
+from app.models import FolderSummary, GitSource
+from app.rag import git_sources as git_sources_resolver
+from app.rag.llm import LLMError
+from app.rag.sources_meta import current_sources_version
+from scripts import import_docs
+from tests.conftest import ADMIN_PASSWORD
+from tests.fakes import FakeEmbedder
+
+# --- shared helpers ---------------------------------------------------------
+
+
+def _folder_calls(llm: FakeEmbedder) -> list[list[dict[str, str]]]:
+    """The ``FOLDER_SUMMARY_MODE`` chat calls on the client (the marker
+    in the system prompt — the KB-overview marker never contains it)."""
+    return [
+        msgs
+        for msgs in llm.chat_calls
+        if any(
+            "FOLDER_SUMMARY_MODE" in m.get("content", "")
+            for m in msgs
+            if m.get("role") == "system"
+        )
+    ]
+
+
+def _rows(db: Session) -> dict[tuple[str, str], str]:
+    """The stored folder summaries as ``{(source, folder_path): summary}``."""
+    db.expire_all()
+    return {
+        (source, folder_path): summary
+        for source, folder_path, summary in db.execute(
+            select(FolderSummary.source, FolderSummary.folder_path, FolderSummary.summary)
+        ).all()
+    }
+
+
+def _updated_at(db: Session, source: str, folder_path: str) -> datetime | None:
+    db.expire_all()
+    row = db.get(FolderSummary, (source, folder_path))
+    return row.updated_at if row is not None else None
+
+
+class FolderFailingChatEmbedder(FakeEmbedder):
+    """``lite`` stand-in that fails exactly one folder-summary call —
+    the one whose user message contains *fail_label* (a ``Folder: …``
+    header) — and answers everything else (incl. the KB overview)
+    normally. Drives the per-folder fail-soft path."""
+
+    def __init__(self, fail_label: str) -> None:
+        super().__init__()
+        self.fail_label = fail_label
+
+    async def chat(
+        self, messages: list[dict[str, str]], model: str | None = None
+    ) -> str:
+        user = next((m["content"] for m in messages if m.get("role") == "user"), "")
+        if self.fail_label in user:
+            self.chat_calls.append(list(messages))
+            raise LLMError("simulated folder-summary outage (test sentinel)")
+        return await super().chat(messages, model)
+
+
+# --- fixtures ----------------------------------------------------------------
+
+
+@pytest.fixture(autouse=True)
+def _clean_kb(db: Session) -> Iterator[None]:
+    """Global KB + registry state, truncated around every test (the
+    real import and the real generator write ``documents``/``chunks``/
+    ``folder_summaries``; the API tests seed ``git_sources``)."""
+    db.execute(
+        text("TRUNCATE chunks, documents, kb_overview, folder_summaries, git_sources")
+    )
+    db.commit()
+    yield
+    db.execute(
+        text("TRUNCATE chunks, documents, kb_overview, folder_summaries, git_sources")
+    )
+    db.commit()
+
+
+@pytest.fixture(autouse=True)
+def _reset_sources_version() -> Iterator[None]:
+    """The sources version counter is global mutable state — pin it to
+    the migration-0010 seed (0) around every test (own session: both
+    sync paths bump through their own short-lived ``SessionLocal``).
+    Skips like the ``db`` fixture when Postgres is down."""
+    if not db_available():
+        pytest.skip("Postgres not reachable — run `podman compose up -d db` first")
+    session = SessionLocal()
+    try:
+        session.execute(text("UPDATE sources_meta SET version = 0 WHERE id = 1"))
+        session.commit()
+        yield
+    finally:
+        session.execute(text("UPDATE sources_meta SET version = 0 WHERE id = 1"))
+        session.commit()
+        session.close()
+
+
+@pytest.fixture(autouse=True)
+def _fresh_sync_state() -> Iterator[None]:
+    """The module-level status object + task are process-global: reset
+    them around every test (harmless for the script-path tests)."""
+    sync_api._status = sync_api.SyncStatus()
+    sync_api._task = None
+    yield
+    sync_api._status = sync_api.SyncStatus()
+    sync_api._task = None
+
+
+@pytest.fixture()
+def src(tmp_path: Path) -> Path:
+    """MyDocs: a/ (2 docs) + b/ (1 doc) → subtree counts root 3, a 2, b 1.
+
+    md → no document-summary chat calls, so the ``lite`` traffic is
+    exactly the overview + the folder summaries."""
+    root = tmp_path / "MyDocs"
+    (root / "a").mkdir(parents=True)
+    (root / "b").mkdir()
+    (root / "a" / "one.md").write_text("# A One\nFirst folder document.\n", encoding="utf-8")
+    (root / "a" / "two.md").write_text("# A Two\nSecond folder document.\n", encoding="utf-8")
+    (root / "b" / "three.md").write_text("# B Three\nLone folder document.\n", encoding="utf-8")
+    return root
+
+
+def _run_main(
+    monkeypatch: pytest.MonkeyPatch,
+    llm: FakeEmbedder,
+    argv: list[str],
+    capsys: pytest.CaptureFixture[str],
+) -> tuple[int, str]:
+    """Run ``import_docs.main`` with fresh settings, a fake LLM, and a
+    fail-loud git mock (``--source`` always wins, so git must stay
+    idle) — the phase-31 overview test's runner."""
+    monkeypatch.setattr(
+        import_docs,
+        "get_settings",
+        lambda: Settings(_env_file=None),  # pyright: ignore[reportCallIssue]
+    )
+
+    def _no_git(url: str, dest: Path | str) -> Path:
+        raise AssertionError("git sync must not run with explicit --source")
+
+    monkeypatch.setattr(import_docs, "clone_or_pull", _no_git)
+    monkeypatch.setattr(import_docs, "LLMClient", lambda: llm)
+    rc = import_docs.main(argv)
+    return rc, capsys.readouterr().out
+
+
+# --- script path: scripts/import_docs.py -------------------------------------
+
+
+def test_changed_import_generates_folder_rows(
+    db: Session,
+    src: Path,
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """A KB-changing import upserts one row per ≥ 2-doc subtree in the
+    run's own transaction — committed and visible afterwards — with the
+    stats on the summary line (PLAN §9)."""
+    llm = FakeEmbedder()
+    records: list[logging.LogRecord] = []
+
+    class _Sink(logging.Handler):
+        def emit(self, record: logging.LogRecord) -> None:
+            records.append(record)
+
+    fs_logger = logging.getLogger("app.rag.folder_summaries")
+    sink = _Sink()
+    fs_logger.addHandler(sink)
+    fs_logger.setLevel(logging.INFO)
+    try:
+        rc, out = _run_main(monkeypatch, llm, ["--source", str(src)], capsys)
+    finally:
+        fs_logger.removeHandler(sink)
+
+    assert rc == 0
+    assert "added=3" in out
+    assert out.rstrip().endswith(
+        "overview=updated sources_version=1 folder_summaries=2/0/0"
+    )
+    # Two FOLDER_SUMMARY_MODE calls — the source root (3 docs) and the
+    # 2-doc folder a; the 1-doc folder b gets no row (no lite burn).
+    calls = _folder_calls(llm)
+    assert len(calls) == 2
+    headers = [c[1]["content"].splitlines()[0] for c in calls]
+    assert headers == ["Folder: MyDocs", "Folder: MyDocs/a"]
+    for c in calls:
+        assert "FOLDER_SUMMARY_MODE" in c[0]["content"]
+    # The rows land committed (the run's own session committed them) —
+    # one per ≥ 2-doc subtree, never empty, stamped.
+    rows = _rows(db)
+    assert set(rows) == {("MyDocs", ""), ("MyDocs", "a")}
+    assert all(rows.values())
+    assert _updated_at(db, "MyDocs", "a") is not None
+    # The stats log line (PLAN §9 ample logging).
+    assert any(
+        "folder_summaries: generated=2 failed=0 pruned=0" in r.getMessage()
+        for r in records
+    )
+
+
+def test_unchanged_reimport_burns_zero_folder_calls(
+    db: Session,
+    src: Path,
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """Same hashes → no KB change → the populated table stays untouched
+    and zero ``lite`` calls burn (overview AND folder summaries)."""
+    llm1 = FakeEmbedder()
+    rc, out = _run_main(monkeypatch, llm1, ["--source", str(src)], capsys)
+    assert rc == 0
+    assert out.rstrip().endswith(
+        "overview=updated sources_version=1 folder_summaries=2/0/0"
+    )
+    rows = _rows(db)
+    assert set(rows) == {("MyDocs", ""), ("MyDocs", "a")}
+
+    llm2 = FakeEmbedder()
+    rc, out = _run_main(monkeypatch, llm2, ["--source", str(src)], capsys)
+    assert rc == 0
+    assert "unchanged=3" in out
+    assert out.rstrip().endswith(
+        "overview=skipped sources_version=skipped folder_summaries=skipped"
+    )
+    assert llm2.chat_calls == []  # zero lite calls, any mode
+    assert _rows(db) == rows  # rows byte-identical
+
+
+def test_subtree_dropping_below_two_docs_is_pruned(
+    db: Session,
+    src: Path,
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """A subtree that drops below the ≥ 2 rule on a changed re-walk
+    loses its (stale) row; the remaining qualifiers regenerate."""
+    llm1 = FakeEmbedder()
+    rc, _ = _run_main(monkeypatch, llm1, ["--source", str(src)], capsys)
+    assert rc == 0
+    assert set(_rows(db)) == {("MyDocs", ""), ("MyDocs", "a")}
+
+    # a/ loses one of its two docs (below the ≥ 2 rule) while b's doc
+    # changes → the re-walk is a KB change, so generation runs and the
+    # stale a/ row is pruned; b (1 doc) still gets no row.
+    (src / "a" / "two.md").unlink()
+    (src / "b" / "three.md").write_text("# B Three\nChanged content.\n", encoding="utf-8")
+    llm2 = FakeEmbedder()
+    rc, out = _run_main(monkeypatch, llm2, ["--source", str(src), "--prune"], capsys)
+
+    assert rc == 0
+    assert "pruned=1" in out
+    assert "updated=1" in out
+    assert out.rstrip().endswith(
+        "overview=updated sources_version=2 folder_summaries=1/0/1"
+    )
+    # Only the source root (the 2 remaining docs) still qualifies.
+    assert set(_rows(db)) == {("MyDocs", "")}
+    assert _updated_at(db, "MyDocs", "a") is None  # the row is gone
+
+
+def test_folder_lite_failure_keeps_previous_row_and_stays_green(
+    db: Session,
+    src: Path,
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """One folder's ``lite`` failure: its previous row is kept, the
+    other folder lands, and the run's exit code stays 0 — the stats
+    carry the failure (``1/1/0``)."""
+    llm1 = FakeEmbedder()
+    rc, _ = _run_main(monkeypatch, llm1, ["--source", str(src)], capsys)
+    assert rc == 0
+    rows_before = _rows(db)
+    a_stamp_before = _updated_at(db, "MyDocs", "a")
+    root_stamp_before = _updated_at(db, "MyDocs", "")
+    assert a_stamp_before is not None and root_stamp_before is not None
+
+    # a/ changes (a KB change → generation runs); lite fails for a/
+    # only — its previous row must stay, the root row must land.
+    (src / "a" / "one.md").write_text("# A One\nChanged content.\n", encoding="utf-8")
+    llm2 = FolderFailingChatEmbedder(fail_label="Folder: MyDocs/a")
+    rc, out = _run_main(monkeypatch, llm2, ["--source", str(src)], capsys)
+
+    assert rc == 0  # a failed folder must not fail the import
+    assert "updated=1" in out
+    assert out.rstrip().endswith(
+        "overview=updated sources_version=2 folder_summaries=1/1/0"
+    )
+    rows_after = _rows(db)
+    assert rows_after["MyDocs", "a"] == rows_before["MyDocs", "a"]  # kept
+    assert _updated_at(db, "MyDocs", "a") == a_stamp_before  # untouched
+    root_stamp_after = _updated_at(db, "MyDocs", "")
+    assert root_stamp_after is not None and root_stamp_after > root_stamp_before
+
+
+def test_limit_run_skips_folder_generation(
+    db: Session,
+    src: Path,
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """A ``--limit`` debug run (an incomplete walk) never generates —
+    no ``lite`` call at all, no rows, the line says ``skipped``."""
+    llm = FakeEmbedder()
+    rc, out = _run_main(monkeypatch, llm, ["--source", str(src), "--limit", "2"], capsys)
+    assert rc == 0
+    assert "added=2" in out
+    assert out.rstrip().endswith(
+        "overview=skipped sources_version=skipped folder_summaries=skipped"
+    )
+    assert llm.chat_calls == []  # no lite call, any mode
+    assert _rows(db) == {}  # an incomplete walk never writes rows
+
+
+def test_empty_table_generates_on_unchanged_walk(
+    db: Session,
+    src: Path,
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """The table-empty first-run trigger: after a ``--limit`` first
+    walk (populated KB, empty table), an unchanged full walk generates
+    — for the folder summaries AND the missing outline, still never
+    bumping the version."""
+    llm1 = FakeEmbedder()
+    rc, out = _run_main(monkeypatch, llm1, ["--source", str(src), "--limit", "3"], capsys)
+    assert rc == 0
+    assert "added=3" in out
+    assert out.rstrip().endswith(
+        "overview=skipped sources_version=skipped folder_summaries=skipped"
+    )
+    assert _rows(db) == {}
+
+    llm2 = FakeEmbedder()
+    rc, out = _run_main(monkeypatch, llm2, ["--source", str(src)], capsys)
+    assert rc == 0
+    assert "unchanged=3" in out
+    assert out.rstrip().endswith(
+        "overview=updated sources_version=skipped folder_summaries=2/0/0"
+    )
+    assert set(_rows(db)) == {("MyDocs", ""), ("MyDocs", "a")}
+    assert len(_folder_calls(llm2)) == 2
+    assert current_sources_version(db) == 0  # the unchanged walk never bumps
+
+
+# --- API path: POST /api/sync -------------------------------------------------
+
+
+@pytest.fixture()
+def sync_client() -> Iterator[TestClient]:
+    """Context-managed TestClient — one app event loop across requests
+    (the background task must survive between the POST and the polls)."""
+    with TestClient(fastapi_app) as client:
+        yield client
+
+
+def _settings(sources_dir: str) -> Settings:
+    return Settings(_env_file=None, sources_dir=sources_dir)  # pyright: ignore[reportCallIssue]
+
+
+def _stub_env(monkeypatch: pytest.MonkeyPatch, git_sources: str = "") -> None:
+    """The resolver's env fallback, driven by a fresh ``Settings`` (the
+    dev ``.env`` never leaks in)."""
+    monkeypatch.setattr(
+        git_sources_resolver,
+        "get_settings",
+        lambda: Settings(_env_file=None, git_sources=git_sources),  # pyright: ignore[reportCallIssue]
+    )
+
+
+def _seed_local(db: Session, path: Path) -> None:
+    """A ``kind=local`` row as the phase-38 API stores it: the expanded
+    absolute path in both ``path`` and the NOT-NULL ``url`` column."""
+    db.add(GitSource(url=str(path), kind="local", path=str(path)))
+    db.commit()
+
+
+def _capture_llm(monkeypatch: pytest.MonkeyPatch) -> list[FakeEmbedder]:
+    """The pipeline's ``LLMClient`` becomes a recorded
+    ``FakeEmbedder`` (real import + real generator, no network)."""
+    clients: list[FakeEmbedder] = []
+
+    def _factory() -> FakeEmbedder:
+        client = FakeEmbedder()
+        clients.append(client)
+        return client
+
+    monkeypatch.setattr(sync_api, "LLMClient", _factory)
+    return clients
+
+
+def _login(client: TestClient) -> None:
+    r = client.post("/api/login", json={"password": ADMIN_PASSWORD})
+    assert r.status_code == 204, f"admin login failed: {r.status_code} {r.text}"
+
+
+def _poll(client: TestClient, want: str, timeout: float = 10.0) -> dict:
+    """Poll ``GET /api/sync/status`` until ``state == want`` (terminal).
+
+    Any state other than ``running`` before the deadline fails loudly —
+    an unexpected ``failed`` must never be masked by the wait."""
+    deadline = time.monotonic() + timeout
+    while time.monotonic() < deadline:
+        body = client.get("/api/sync/status").json()
+        if body["state"] == want:
+            return body
+        assert body["state"] == "running", (
+            f"unexpected state {body['state']!r} while waiting for {want!r}: {body}"
+        )
+        time.sleep(0.05)
+    raise AssertionError(f"sync did not reach {want!r} within {timeout}s")
+
+
+@pytest.fixture()
+def local_dir(tmp_path: Path) -> Path:
+    """LocalDocs: a/ (2 docs) → subtree counts root 2, a 2 (one
+    qualifying source-root row + one folder row)."""
+    d = tmp_path / "LocalDocs"
+    (d / "a").mkdir(parents=True)
+    (d / "a" / "one.md").write_text("# A One\nfirst local file\n", encoding="utf-8")
+    (d / "a" / "two.md").write_text("# A Two\nsecond local file\n", encoding="utf-8")
+    return d
+
+
+def test_api_changed_sync_generates_folder_rows(
+    sync_client: TestClient,
+    monkeypatch: pytest.MonkeyPatch,
+    db: Session,
+    local_dir: Path,
+) -> None:
+    """A KB-changing sync upserts the rows (visible via the test's own
+    session) and keeps the status detail's exact pre-phase shape — the
+    folder stats are log-only, not a new status surface."""
+    _seed_local(db, local_dir)
+    _stub_env(monkeypatch)
+    monkeypatch.setattr(
+        sync_api,
+        "get_settings",
+        lambda: _settings(str(local_dir.parent / "bor")),
+    )
+    clients = _capture_llm(monkeypatch)
+
+    _login(sync_client)
+    assert sync_client.post("/api/sync").status_code == 202
+    body = _poll(sync_client, "success")
+
+    assert body["error"] is None
+    # No new sync-status surface: the detail keeps its exact key set.
+    assert set(body["detail"]) == {
+        "files", "added", "updated", "unchanged", "pruned", "errors",
+        "chunks", "summaries", "summary_errors", "overview",
+        "sources_version",
+    }
+    assert body["detail"]["files"] == 2
+    assert body["detail"]["added"] == 2
+    assert body["detail"]["overview"] is True
+    assert body["detail"]["sources_version"] == 1
+    # One LLM client for probe + import + overview + folder summaries;
+    # exactly two FOLDER_SUMMARY_MODE calls (root + the 2-doc a/ folder).
+    assert len(clients) == 1
+    calls = _folder_calls(clients[0])
+    assert len(calls) == 2
+    headers = [c[1]["content"].splitlines()[0] for c in calls]
+    assert headers == ["Folder: LocalDocs", "Folder: LocalDocs/a"]
+    # The rows land committed — visible from the test's own session.
+    rows = _rows(db)
+    assert set(rows) == {("LocalDocs", ""), ("LocalDocs", "a")}
+    assert all(rows.values())
+    assert current_sources_version(db) == 1
+
+
+def test_api_unchanged_resync_burns_zero_folder_calls(
+    sync_client: TestClient,
+    monkeypatch: pytest.MonkeyPatch,
+    db: Session,
+    local_dir: Path,
+) -> None:
+    """Same files → unchanged re-sync: no ``lite`` call of any kind
+    (populated table), rows untouched, version unadvanced."""
+    _seed_local(db, local_dir)
+    _stub_env(monkeypatch)
+    monkeypatch.setattr(
+        sync_api,
+        "get_settings",
+        lambda: _settings(str(local_dir.parent / "bor")),
+    )
+    clients = _capture_llm(monkeypatch)
+
+    _login(sync_client)
+    assert sync_client.post("/api/sync").status_code == 202
+    _poll(sync_client, "success")
+    rows = _rows(db)
+    assert set(rows) == {("LocalDocs", ""), ("LocalDocs", "a")}
+
+    assert sync_client.post("/api/sync").status_code == 202
+    body = _poll(sync_client, "success")
+    assert body["detail"]["overview"] is False
+    assert body["detail"]["sources_version"] == 1  # unchanged → no bump
+    assert len(clients) == 2
+    # Zero GENERATION calls — no folder summary, no KB overview. The
+    # only chat the re-sync's client makes is the phase-41 probe's ping.
+    assert _folder_calls(clients[1]) == []
+    assert all(
+        "KB_OVERVIEW_MODE" not in m.get("content", "")
+        for msgs in clients[1].chat_calls
+        for m in msgs
+        if m.get("role") == "system"
+    )
+    assert len(clients[1].chat_calls) == 1
+    assert clients[1].chat_calls[0][0]["content"] == "ping"
+    assert _rows(db) == rows
+    assert current_sources_version(db) == 1
+
+
+
+def test_api_folder_lite_failure_keeps_rows_stays_green_and_bumps(
+    sync_client: TestClient,
+    monkeypatch: pytest.MonkeyPatch,
+    db: Session,
+    local_dir: Path,
+) -> None:
+    """A ``lite`` outage for one folder: the run stays ``success``
+    (never ``failed``), the failed folder's previous row is kept, the
+    rest regenerates, and the sources-version bump still lands (the
+    bump is change-gated on the KB, not on the summaries)."""
+    _seed_local(db, local_dir)
+    _stub_env(monkeypatch)
+    monkeypatch.setattr(
+        sync_api,
+        "get_settings",
+        lambda: _settings(str(local_dir.parent / "bor")),
+    )
+    clients = _capture_llm(monkeypatch)
+
+    _login(sync_client)
+    assert sync_client.post("/api/sync").status_code == 202
+    _poll(sync_client, "success")
+    rows_before = _rows(db)
+    a_stamp_before = _updated_at(db, "LocalDocs", "a")
+    root_stamp_before = _updated_at(db, "LocalDocs", "")
+    assert a_stamp_before is not None and root_stamp_before is not None
+    assert len(clients) == 1  # sync 1 used the recording factory
+
+    # a/ changes (the KB changes) while lite fails for a/ only.
+    (local_dir / "a" / "one.md").write_text(
+        "# A One\nchanged local file\n", encoding="utf-8"
+    )
+    monkeypatch.setattr(
+        sync_api,
+        "LLMClient",
+        lambda: FolderFailingChatEmbedder(fail_label="Folder: LocalDocs/a"),
+    )
+    assert sync_client.post("/api/sync").status_code == 202
+    body = _poll(sync_client, "success")  # GREEN — a lite outage is fail-soft
+
+    assert body["error"] is None
+    assert body["detail"]["updated"] == 1
+    assert body["detail"]["sources_version"] == 2  # the bump was not blocked
+    assert current_sources_version(db) == 2
+    rows_after = _rows(db)
+    assert rows_after["LocalDocs", "a"] == rows_before["LocalDocs", "a"]
+    assert _updated_at(db, "LocalDocs", "a") == a_stamp_before  # kept as-is
+    root_stamp_after = _updated_at(db, "LocalDocs", "")
+    assert root_stamp_after is not None and root_stamp_after > root_stamp_before
+
+
+def test_api_empty_table_first_sync_regenerates(
+    sync_client: TestClient,
+    monkeypatch: pytest.MonkeyPatch,
+    db: Session,
+    local_dir: Path,
+) -> None:
+    """The migration-0017 scenario: the KB predates the table — wipe
+    the rows and re-sync an unchanged KB: the empty-table trigger
+    fires for the folder summaries (the overview's API gate, purely
+    change-gated, does not)."""
+    _seed_local(db, local_dir)
+    _stub_env(monkeypatch)
+    monkeypatch.setattr(
+        sync_api,
+        "get_settings",
+        lambda: _settings(str(local_dir.parent / "bor")),
+    )
+    clients = _capture_llm(monkeypatch)
+
+    _login(sync_client)
+    assert sync_client.post("/api/sync").status_code == 202
+    _poll(sync_client, "success")
+    assert set(_rows(db)) == {("LocalDocs", ""), ("LocalDocs", "a")}
+
+    db.execute(text("TRUNCATE folder_summaries"))
+    db.commit()
+    assert sync_client.post("/api/sync").status_code == 202
+    body = _poll(sync_client, "success")
+
+    assert body["detail"]["overview"] is False  # unchanged → no overview
+    assert body["detail"]["sources_version"] == 1  # unchanged → no bump
+    assert len(clients) == 2
+    assert len(_folder_calls(clients[1])) == 2  # the folders regenerated
+    assert set(_rows(db)) == {("LocalDocs", ""), ("LocalDocs", "a")}

tests/unit/test_agent.py

@@ -2,15 +2,20 @@
 harness-aligned ``ls``/``read``/``grep`` surface, phase 70).
 
 A scripted fake LLM (canned stream sequences) + monkeypatched
-``list_catalog`` / ``list_source_names`` / ``find_document`` /
+``ls_top`` / ``ls_folder`` / ``list_source_names`` / ``find_document`` /
 ``all_documents`` — no database, no network. Covers the loop mechanics:
 the ls → read (combined ``source/path``) → answer happy path (event
 order, holder state, the tools staying offered on every request —
 phase 45 removed the per-tool budgets, the assistant/tool message
-history), the ``ls`` scoping (no-arg full catalog in the phase-63
+history), the phase-94 drill-down ``ls`` (no-arg top level = the
-labeled-field format, a one-source scope, a known source with 0
+registered sources with counts + stored summaries in the pinned
-documents → ``0 documents:`` counted, an unknown-source refusal that
+``{N} sources:`` template, a source scope = its root folder —
-counts nothing), ``read`` on the canonical combined form (split at the
+subfolders + capped file lines in the pinned folder template —, a
+``source/folder`` scope = one level deeper, a registered source with 0
+documents → the ``… — 0 documents, 0 folders:`` header counted, an
+unknown-source refusal that counts nothing, the NOT-A-FOLDER teaching
+with the parent's subfolders, the 50-file cap + grep-pointer note),
+``read`` on the canonical combined form (split at the
 FIRST slash, full content, the bare-source-name refusal, the
 already-in-context dedupe, missing-args refusals), the phase-68 ``grep``
 contract under its new name (the locked A5 pins: fixed substring,
@@ -149,28 +154,35 @@ def test_agent_tools_names_and_parameters() -> None:
     # Task 05 (live gate iteration 2): the one-call-at-a-time discipline
     # clause (the harness prior batches calls; the loop executes one
     # per round — the extras count as unexecuted in the gate).
+    # Phase 94 (task 03): the description is the drill-down tree
+    # contract (pinned copy — the tool-surface revision, owner
+    # permission 2026-09-10, ``TODO.md`` L4): one level per call,
+    # sources at the top, folders + files below, the file-line format
+    # and the combined-identity handoff to read/grep intact.
     assert ls["description"] == (
-        "List the indexed documents as `source: X | path: Y | "
+        "List the knowledge base as a tree, one level at a time. "
-        "title: Z` lines. Call one tool at a time — wait for "
+        "With no path: the synced sources — each with its document "
-        "this result before your next call."
+        "count and a summary of its contents. With a source name (no "
+        "'/'): that source's top-level folders and files. With a "
+        "`source/folder` path: that folder's subfolders and files. "
+        "Folder lines carry a summary of what the folder contains. "
+        "File lines are `source: X | path: Y | title: Z` — use the "
+        "combined `source/path` with `read` and `grep`. Call one tool "
+        "at a time — wait for this result before your next call."
     )
     ls_params = ls["parameters"]
     assert ls_params["type"] == "object"
     assert ls_params["required"] == []  # path is optional
     assert set(ls_params["properties"]) == {"path"}
     assert ls_params["properties"]["path"]["type"] == "string"
-    # Phase 72: the description states the contract up front — the
+    # Phase 94 (task 03): the 'path' argument teaches the drill-down
-    # 'path' argument is a source name, not a file or directory path.
+    # semantics — a source name lists that source's top level, a
-    # Task 05 (live gate iteration 5): the cross-tool contrast clause
+    # `source/folder` path drills one level deeper, omitted lists
-    # (ls is the ONLY tool whose path is a source name — the model
+    # every source (pinned copy).
-    # kept transferring that scope to grep's document identity).
     assert ls_params["properties"]["path"]["description"] == (
-        "Source name to list one source's documents (e.g. 'homelab') — "
+        "Optional — a source name (e.g. 'homelab') to list its top "
-        "a source name, not a file or directory path; omit to list "
+        "level, or a `source/folder` path to drill down (e.g. "
-        "every document. This is the only tool "
+        "'homelab/active'). Omit it to list every source."
-        "whose `path` is a source name — for "
-        "`read` and `grep` it must be a document's "
-        "combined `source/path`."
     )
     read = by_name["read"]["function"]
     # Tool-calling fast loop (2026-09-04, controlled fixture gate):
@@ -285,16 +297,11 @@ def test_refusal_constants_are_harness_aligned() -> None:
     assert agent.UNKNOWN_TOOL == "Unknown tool."
     assert agent.MISSING_READ_ARGS == "read requires a string argument 'path'."
     assert agent.MISSING_SEARCH_ARGS == "grep requires a string argument 'pattern'."
-    # Phase 72: the ls teaching-refusal templates, pinned byte-for-byte
+    # Phase 94 (task 03): the phase-72 document-path teaching refusal is
-    # (task 01 — the read/grep suggestion templates below, task 02).
+    # DELETED (a ``/`` now names a folder — the drill-down contract);
-    assert agent.LS_PATH_NOT_A_SOURCE == (
+    # the no-source refusal stays byte-identical (the task's "existing
-        "'{path}' looks like a document path, not a source name. The "
+    # refusal, teaching parenthetical intact" pin).
-        "'path' argument of ls filters by source name (e.g. 'homelab') — "
+    assert not hasattr(agent, "LS_PATH_NOT_A_SOURCE")
-        "omit it to list every document, or read a document by its "
-        "combined 'source/path' string."
-    )
-    # The pre-phase-72 no-source line is the byte-identical prefix of
-    # the extended line — only the teaching parenthetical was appended.
     assert agent.NO_SOURCE_NOT_A_DIRECTORY.startswith(
         "No source named '{scope}' — check the ls output."
     )
@@ -303,6 +310,11 @@ def test_refusal_constants_are_harness_aligned() -> None:
         "argument is a source name, not a directory — omit it to list "
         "every document.)"
     )
+    # Phase 94 (task 03): the NOT-A-FOLDER drill-down teaching template,
+    # pinned byte-for-byte (argument echoed, parent's subfolders
+    # listed), and the pinned file-line cap constant.
+    assert agent.NOT_A_FOLDER == "'{arg}' is not a folder — {parent} has: {subfolders}"
+    assert agent.LS_MAX_FILE_LINES == 50
     # Phase 72 (task 02): the read/grep "did you mean …?" suggestion
     # templates, pinned byte-for-byte, and the suggestion cap.
     assert agent.NO_DOCUMENT_DID_YOU_MEAN == (
@@ -348,11 +360,12 @@ def test_list_source_names_empty_registry(monkeypatch: pytest.MonkeyPatch) -> No
 
 
 def test_ls_then_read_then_answer(monkeypatch: pytest.MonkeyPatch) -> None:
-    catalog = [
+    # Phase 94 (task 03): the no-arg ``ls`` is the drill-down TOP level
-        ("Deployments", "backups.md", "Backup Strategy"),
+    # (the registered sources, registry order) — monkeypatched the way
-        ("Homelab", "aws-route53.md", "AWS Route53 Records"),
+    # the phase-70 full-catalog listing used to be.
-    ]
+    monkeypatch.setattr(
-    monkeypatch.setattr(agent, "list_catalog", lambda db: catalog)
+        agent, "ls_top", lambda db: [("Deployments", 1, None), ("Homelab", 1, None)]
+    )
     target = _doc("Homelab", "aws-route53.md", "AWS Route53 Records", "R53-CONTENT")
     calls: list[tuple[str, str]] = []
 
@@ -423,11 +436,7 @@ def test_ls_then_read_then_answer(monkeypatch: pytest.MonkeyPatch) -> None:
     assert msgs[3] == {
         "role": "tool",
         "tool_call_id": "call_1",
-        "content": (
+        "content": "2 sources:\n\nDeployments — 1 documents\nHomelab — 1 documents",
-            "2 documents:\n"
-            "source: Deployments | path: backups.md | title: Backup Strategy\n"
-            "source: Homelab | path: aws-route53.md | title: AWS Route53 Records"
-        ),
     }
     # The second follow-up request carries the read call + the FULL text.
     msgs = llm.requests[2][0]
@@ -448,7 +457,7 @@ def test_content_and_tool_call_in_one_stream_keeps_both(
 ) -> None:
     """Rare stream with content AND a tool call: the content stays (it was
     already emitted) and the tool still runs."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [])
+    monkeypatch.setattr(agent, "ls_top", lambda db: [])
     holder = AgentHolder()
     llm = ScriptedLLM(
         [
@@ -460,7 +469,7 @@ def test_content_and_tool_call_in_one_stream_keeps_both(
     pieces = asyncio.run(_run(llm, holder, _settings()))
     assert [type(p) for p in pieces] == [StreamPiece, ToolCallPiece, StreamPiece]
     assert holder.tool_calls == 1  # the tool ran despite the content
-    assert llm.requests[1][0][3]["content"] == "0 documents:\n"
+    assert llm.requests[1][0][3]["content"] == "0 sources:"
 
 
 # ---------- phase 74: client history between system and user ----------
@@ -519,7 +528,7 @@ def test_run_agent_history_survives_a_tool_round(
     """The tool rounds append assistant/tool messages to the SAME
     ``messages`` list — the prior history stays in place between the
     system prompt and the current question on the SECOND request too."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [])
+    monkeypatch.setattr(agent, "ls_top", lambda db: [])
     llm = ScriptedLLM(
         [ToolCallPiece(id="call_1", name="ls", arguments={})],
         [StreamPiece("content", "the answer")],
@@ -534,22 +543,25 @@ def test_run_agent_history_survives_a_tool_round(
     ]
 
 
-# ---------- ls: full catalog + scoping ----------
+# ---------- ls: the drill-down tree (phase 94, task 03) ----------
 
 
-def test_ls_full_catalog_format(monkeypatch: pytest.MonkeyPatch) -> None:
+def test_ls_top_level_lists_sources_with_summaries(
-    """No argument: the full catalog in the phase-63 labeled-field format
+    monkeypatch: pytest.MonkeyPatch,
-    (``source: X | path: Y | title: Z``) — counted; no registry lookup."""
+) -> None:
-    catalog = [
+    """No argument: the TOP level — the registered sources, registry
-        ("Deployments", "backups.md", "Backup Strategy"),
+    order, each ``{source} — {n} documents`` + the indented summary line
-        ("Homelab", "aws-route53.md", "AWS Route53 Records"),
+    only when stored — the pinned template, counted; the registry IS
-    ]
+    consulted (unlike the phase-70 full catalog, the top level is the
-    monkeypatch.setattr(agent, "list_catalog", lambda db: catalog)
+    registry itself)."""
-
+    monkeypatch.setattr(
-    def _boom_sources(*_a: Any, **_k: Any) -> None:
+        agent,
-        raise AssertionError("no registry lookup for an unscoped ls")
+        "ls_top",
-
+        lambda db: [
-    monkeypatch.setattr(agent, "list_source_names", _boom_sources)
+            ("Deployments", 0, None),
+            ("Homelab", 1, "The homelab notes."),
+        ],
+    )
     holder = AgentHolder()
     llm = ScriptedLLM(
         [ToolCallPiece(id="call_1", name="ls", arguments={})],
@@ -557,22 +569,27 @@ def test_ls_full_catalog_format(monkeypatch: pytest.MonkeyPatch) -> None:
     )
     asyncio.run(_run(llm, holder, _settings()))
     assert llm.requests[1][0][3]["content"] == (
-        "2 documents:\n"
+        "2 sources:\n"
-        "source: Deployments | path: backups.md | title: Backup Strategy\n"
+        "\n"
-        "source: Homelab | path: aws-route53.md | title: AWS Route53 Records"
+        "Deployments — 0 documents\n"
+        "Homelab — 1 documents\n"
+        "  The homelab notes."
     )
     assert holder.tool_calls == 1
 
 
-def test_ls_empty_catalog_says_zero_documents(monkeypatch: pytest.MonkeyPatch) -> None:
+def test_ls_empty_registry_says_zero_sources(monkeypatch: pytest.MonkeyPatch) -> None:
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [])
+    """No registered sources: the top level is the header line alone —
+    ``0 sources:`` (the old ``0 documents:`` behavior preserved in
+    spirit), still a counted result."""
+    monkeypatch.setattr(agent, "ls_top", lambda db: [])
     holder = AgentHolder()
     llm = ScriptedLLM(
         [ToolCallPiece(id="call_1", name="ls", arguments={})],
         [StreamPiece("content", "ans")],
     )
     asyncio.run(_run(llm, holder, _settings()))
-    assert llm.requests[1][0][3]["content"] == "0 documents:\n"
+    assert llm.requests[1][0][3]["content"] == "0 sources:"
     assert holder.tool_calls == 1
 
 
@@ -583,13 +600,12 @@ def test_ls_empty_catalog_says_zero_documents(monkeypatch: pytest.MonkeyPatch) -
         ({"path": 7}, "non-string path"),
     ],
 )
-def test_ls_blank_path_lists_full_catalog(
+def test_ls_blank_path_lists_top_level(
     monkeypatch: pytest.MonkeyPatch, arguments: dict[str, Any], label: str
 ) -> None:
-    """A blank (or non-string) ``path`` is treated as omitted — the full
+    """A blank (or non-string) ``path`` is treated as omitted — the top
-    catalog, counted (no refusal for an empty scope)."""
+    level (the sources), counted (no refusal for an empty scope)."""
-    catalog = [("S", "a.md", "A")]
+    monkeypatch.setattr(agent, "ls_top", lambda db: [("S", 1, None)])
-    monkeypatch.setattr(agent, "list_catalog", lambda db: catalog)
     monkeypatch.setattr(agent, "list_source_names", lambda db: ["S"])
     holder = AgentHolder()
     llm = ScriptedLLM(
@@ -597,21 +613,25 @@ def test_ls_blank_path_lists_full_catalog(
         [StreamPiece("content", "ans")],
     )
     asyncio.run(_run(llm, holder, _settings()))
-    assert (
+    assert llm.requests[1][0][3]["content"] == "1 sources:\n\nS — 1 documents"
-        llm.requests[1][0][3]["content"] == "1 documents:\nsource: S | path: a.md | title: A"
-    )
     assert holder.tool_calls == 1
 
 
-def test_ls_scoped_to_known_source(monkeypatch: pytest.MonkeyPatch) -> None:
+def test_ls_source_scope_lists_root_folder(monkeypatch: pytest.MonkeyPatch) -> None:
-    """A known source name: the same listing filtered to that source —
+    """A registered source name (no ``/``): the source's ROOT folder —
+    subfolders (2-space-indented, path order, ``: {summary}`` only when
+    stored) + the root's own file lines in EXACTLY the
+    ``source: X | path: Y | title: Z`` format — the pinned template,
     counted."""
-    catalog = [
+    monkeypatch.setattr(
-        ("Deployments", "backups.md", "Backup Strategy"),
+        agent,
-        ("Homelab", "a.md", "A"),
+        "ls_folder",
-        ("Homelab", "b.md", "B"),
+        lambda db, source, folder: (
-    ]
+            [("backups", 2, "Backup notes."), ("networking", 1, None)],
-    monkeypatch.setattr(agent, "list_catalog", lambda db: catalog)
+            [("Homelab", "readme.md", "Readme")],
+            1,
+        ),
+    )
     monkeypatch.setattr(agent, "list_source_names", lambda db: ["Deployments", "Homelab"])
     holder = AgentHolder()
     llm = ScriptedLLM(
@@ -620,9 +640,50 @@ def test_ls_scoped_to_known_source(monkeypatch: pytest.MonkeyPatch) -> None:
     )
     asyncio.run(_run(llm, holder, _settings()))
     assert llm.requests[1][0][3]["content"] == (
-        "2 documents:\n"
+        "Homelab — 1 documents, 2 folders:\n"
-        "source: Homelab | path: a.md | title: A\n"
+        "\n"
-        "source: Homelab | path: b.md | title: B"
+        "  backups/ — 2 documents: Backup notes.\n"
+        "  networking/ — 1 documents\n"
+        "\n"
+        "source: Homelab | path: readme.md | title: Readme"
+    )
+    assert holder.tool_calls == 1
+
+
+def test_ls_nested_folder_scope_lists_one_level_deeper(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """A ``source/folder`` path: that folder's subfolders + own file
+    lines, identity = ``source/folder`` (the same template as the
+    root), counted; the fetchers are the source-scoped ones."""
+
+    def _rows(db: Any, source: str) -> list[tuple[str, str]]:
+        assert (source, db) == ("Homelab", None)
+        return [
+            ("networking/lan.md", "LAN"),
+            ("networking/vpn.md", "VPN"),
+        ]
+
+    monkeypatch.setattr(agent, "_source_document_rows", _rows)
+    monkeypatch.setattr(
+        agent, "_source_folder_summaries", lambda db, source: {"networking": "Network notes."}
+    )
+    monkeypatch.setattr(agent, "list_source_names", lambda db: ["Homelab"])
+    holder = AgentHolder()
+    llm = ScriptedLLM(
+        [
+            ToolCallPiece(
+                id="call_1", name="ls", arguments={"path": "Homelab/networking"}
+            )
+        ],
+        [StreamPiece("content", "ans")],
+    )
+    asyncio.run(_run(llm, holder, _settings()))
+    assert llm.requests[1][0][3]["content"] == (
+        "Homelab/networking — 2 documents, 0 folders:\n"
+        "\n"
+        "source: Homelab | path: networking/lan.md | title: LAN\n"
+        "source: Homelab | path: networking/vpn.md | title: VPN"
     )
     assert holder.tool_calls == 1
 
@@ -631,9 +692,13 @@ def test_ls_scoped_known_source_with_zero_docs_counts(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
     """A registered source with no indexed documents is KNOWN (the
-    registry is the source of truth, not the catalog): it lists as
+    registry is the source of truth, not the catalog): it lists its
-    ``0 documents:`` — a valid, counted result, not a refusal."""
+    header line alone (``… — 0 documents, 0 folders:`` — the old
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("Other", "a.md", "A")])
+    ``0 documents:`` behavior preserved in spirit) — a valid, counted
+    result, not a refusal."""
+    monkeypatch.setattr(
+        agent, "ls_folder", lambda db, source, folder: ([], [], 0)
+    )
     monkeypatch.setattr(agent, "list_source_names", lambda db: ["Homelab", "Other"])
     holder = AgentHolder()
     llm = ScriptedLLM(
@@ -641,7 +706,7 @@ def test_ls_scoped_known_source_with_zero_docs_counts(
         [StreamPiece("content", "ans")],
     )
     asyncio.run(_run(llm, holder, _settings()))
-    assert llm.requests[1][0][3]["content"] == "0 documents:\n"
+    assert llm.requests[1][0][3]["content"] == "Homelab — 0 documents, 0 folders:"
     assert holder.tool_calls == 1  # an executed ls, not a refusal
     assert llm.requests[1][1] == AGENT_TOOLS
 
@@ -650,7 +715,6 @@ def test_ls_scoped_unknown_source_refused(monkeypatch: pytest.MonkeyPatch) -> No
     """A ``path`` without ``/`` matching no source name is a refusal —
     the extended line with the teaching parenthetical (phase 72), not
     counted, the round cap bounds its repetition."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
     monkeypatch.setattr(agent, "list_source_names", lambda db: ["S"])
     holder = AgentHolder()
     llm = ScriptedLLM(
@@ -666,20 +730,14 @@ def test_ls_scoped_unknown_source_refused(monkeypatch: pytest.MonkeyPatch) -> No
     assert llm.requests[1][1] == AGENT_TOOLS  # rejected → tools stay offered
 
 
-def test_ls_path_like_scope_gets_document_path_teaching_refusal(
+def test_ls_path_like_scope_unknown_source_gets_no_source_refusal(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
-    """Phase 72: a stripped scope containing ``/`` looks like a document
+    """Phase 94: a ``/`` now names a folder, so the phase-72
-    path (the incident's ``ls(path='app/rag/importer.py')``) — a source
+    document-path teaching is DELETED — a ``source/…`` argument whose
-    name is a directory basename and can never contain one, so this gets
+    FIRST segment names no registered source gets the no-source refusal
-    the ``LS_PATH_NOT_A_SOURCE`` teaching line with the argument echoed;
+    (the segment echoed), counted in nothing, tools stay offered."""
-    no registry lookup, counts in nothing, tools stay offered."""
+    monkeypatch.setattr(agent, "list_source_names", lambda db: ["S"])
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
-
-    def _boom_sources(*_a: Any, **_k: Any) -> None:
-        raise AssertionError("no registry lookup for a path-like scope")
-
-    monkeypatch.setattr(agent, "list_source_names", _boom_sources)
     holder = AgentHolder()
     llm = ScriptedLLM(
         [
@@ -695,7 +753,7 @@ def test_ls_path_like_scope_gets_document_path_teaching_refusal(
     assert holder.tool_calls == 0  # a refusal counts in nothing
     assert (
         llm.requests[1][0][3]["content"]
-        == agent.LS_PATH_NOT_A_SOURCE.format(path="app/rag/importer.py")
+        == agent.NO_SOURCE_NOT_A_DIRECTORY.format(scope="app")
     )
     assert llm.requests[1][1] == AGENT_TOOLS  # rejected → tools stay offered
 
@@ -706,8 +764,7 @@ def test_ls_dot_scope_gets_not_a_directory_teaching_refusal(
     """Phase 72: ``ls(path='.')`` (the incident's second round — no
     ``/``, no matching source) gets the extended no-source refusal with
     the teaching parenthetical, ``'.'`` echoed — not counted, tools stay
-    offered."""
+    offered (unchanged by phase 94)."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
     monkeypatch.setattr(agent, "list_source_names", lambda db: ["S"])
     holder = AgentHolder()
     llm = ScriptedLLM(
@@ -723,6 +780,312 @@ def test_ls_dot_scope_gets_not_a_directory_teaching_refusal(
     assert llm.requests[1][1] == AGENT_TOOLS  # rejected → tools stay offered
 
 
+def test_ls_unknown_top_level_folder_gets_not_a_folder_teaching(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Phase 94: a ``source/…`` argument whose TOP-LEVEL folder segment
+    matches no indexed prefix gets the NOT-A-FOLDER teaching — the
+    argument echoed, the source named, its direct subfolders listed so
+    the model self-corrects in the next round; not counted, tools stay
+    offered."""
+    monkeypatch.setattr(
+        agent,
+        "_source_document_rows",
+        lambda db, source: [
+            ("backups/cron.md", "Cron"),
+            ("containers/caddy.md", "Caddy"),
+            ("networking/lan.md", "LAN"),
+        ],
+    )
+    monkeypatch.setattr(agent, "_source_folder_summaries", lambda db, source: {})
+    monkeypatch.setattr(agent, "list_source_names", lambda db: ["Homelab"])
+    holder = AgentHolder()
+    llm = ScriptedLLM(
+        [
+            ToolCallPiece(
+                id="call_1", name="ls", arguments={"path": "Homelab/netwoking"}
+            )
+        ],
+        [StreamPiece("content", "ans")],
+    )
+    asyncio.run(_run(llm, holder, _settings()))
+    assert holder.tool_calls == 0  # a refusal counts in nothing
+    assert llm.requests[1][0][3]["content"] == (
+        "'Homelab/netwoking' is not a folder — Homelab has: "
+        "backups/ containers/ networking/"
+    )
+    assert llm.requests[1][1] == AGENT_TOOLS  # rejected → tools stay offered
+
+
+def test_ls_unknown_nested_folder_gets_not_a_folder_with_nested_parent(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Phase 94: a nested miss names the DEEPEST existing ancestor —
+    ``source/folder`` — and lists ITS direct subfolders (bounded: the
+    parent's own listing, no new flood path)."""
+    monkeypatch.setattr(
+        agent,
+        "_source_document_rows",
+        lambda db, source: [
+            ("networking/lan/a.md", "A"),
+            ("networking/vpn/b.md", "B"),
+            ("readme.md", "Readme"),
+        ],
+    )
+    monkeypatch.setattr(agent, "_source_folder_summaries", lambda db, source: {})
+    monkeypatch.setattr(agent, "list_source_names", lambda db: ["Homelab"])
+    holder = AgentHolder()
+    llm = ScriptedLLM(
+        [
+            ToolCallPiece(
+                id="call_1", name="ls", arguments={"path": "Homelab/networking/lan/x"}
+            )
+        ],
+        [StreamPiece("content", "ans")],
+    )
+    asyncio.run(_run(llm, holder, _settings()))
+    assert holder.tool_calls == 0
+    assert llm.requests[1][0][3]["content"] == (
+        "'Homelab/networking/lan/x' is not a folder — "
+        "Homelab/networking/lan has: none"
+    )
+
+
+def test_ls_file_path_scope_gets_not_a_folder(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Phase 94: a document's OWN path is never a folder (nothing starts
+    with ``path + '/'``) — ``ls`` of a file path refuses with the
+    NOT-A-FOLDER teaching (the parent's subfolders listed)."""
+    monkeypatch.setattr(
+        agent,
+        "_source_document_rows",
+        lambda db, source: [("notes.md", "Notes"), ("a/b.md", "B")],
+    )
+    monkeypatch.setattr(agent, "_source_folder_summaries", lambda db, source: {})
+    monkeypatch.setattr(agent, "list_source_names", lambda db: ["S"])
+    holder = AgentHolder()
+    llm = ScriptedLLM(
+        [
+            ToolCallPiece(id="call_1", name="ls", arguments={"path": "S/notes.md"})
+        ],
+        [StreamPiece("content", "ans")],
+    )
+    asyncio.run(_run(llm, holder, _settings()))
+    assert holder.tool_calls == 0
+    assert llm.requests[1][0][3]["content"] == (
+        "'S/notes.md' is not a folder — S has: a/"
+    )
+
+
+# ---------- ls_top / ls_folder: the drill-down accessors (pure + composed) ----------
+
+
+def test_ls_top_registry_order_zero_docs_and_summaries(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """``ls_top``: registry order (not catalog order), a 0-document
+    source still lists, the summary is the stored ``(source, "")`` row
+    or ``None`` when absent; an empty registry → ``[]``."""
+    monkeypatch.setattr(agent, "list_source_names", lambda db: ["Zeta", "Alpha"])
+    monkeypatch.setattr(
+        agent, "_source_document_counts", lambda db: [("Zeta", 3), ("Beta", 1)]
+    )
+    monkeypatch.setattr(
+        agent, "_source_root_summaries", lambda db: [("Zeta", "Zeta stuff.")]
+    )
+    assert agent.ls_top(cast("Session", object())) == [
+        ("Zeta", 3, "Zeta stuff."),
+        ("Alpha", 0, None),  # 0 docs (no count row) + no stored summary
+    ]
+
+
+def test_ls_top_empty_registry_is_empty(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr(agent, "list_source_names", lambda db: [])
+
+    def _boom(*_a: Any, **_k: Any) -> None:
+        raise AssertionError("no fetches for an empty registry")
+
+    monkeypatch.setattr(agent, "_source_document_counts", _boom)
+    monkeypatch.setattr(agent, "_source_root_summaries", _boom)
+    assert agent.ls_top(cast("Session", object())) == []
+
+
+def test_ls_folder_composes_the_fetchers(monkeypatch: pytest.MonkeyPatch) -> None:
+    """``ls_folder`` = the source's document rows + stored summaries
+    through the pure :func:`group_folder_listing` (the fetchers are the
+    monkeypatch surface)."""
+    seen: list[tuple[str, str, str]] = []
+
+    def _rows(db: Any, source: str) -> list[tuple[str, str]]:
+        seen.append(("rows", source, ""))
+        return [("a/b.md", "B"), ("a.md", "A")]
+
+    def _summaries(db: Any, source: str) -> dict[str, str]:
+        seen.append(("summaries", source, ""))
+        return {"a": "A stuff."}
+
+    monkeypatch.setattr(agent, "_source_document_rows", _rows)
+    monkeypatch.setattr(agent, "_source_folder_summaries", _summaries)
+    assert agent.ls_folder(cast("Session", object()), "S", "") == (
+        [("a", 1, "A stuff.")],
+        [("S", "a.md", "A")],
+        1,
+    )
+    assert seen == [("rows", "S", ""), ("summaries", "S", "")]
+
+
+def test_group_folder_listing_subfolder_recursion_and_counts() -> None:
+    """The recursive count per subfolder — every path equal to the
+    folder or starting with ``folder + '/'`` (a doc under ``a/b/``
+    counts for BOTH ``a`` and ``a/b``), path order, the stored summary
+    attached or ``None``."""
+    rows = [
+        ("a/b/c.md", "C"),
+        ("a/b/d.md", "D"),
+        ("a/e.md", "E"),
+        ("f.md", "F"),
+    ]
+    sub, files, total = agent.group_folder_listing(
+        "S", "", rows, {"a": "A subtree.", "a/b": "B subtree."}
+    )
+    # ROOT level: the direct subfolders of "" are the TOP-LEVEL folders
+    # only (a/b is nested under a, not direct) — a's count is its whole
+    # recursive subtree (a/e.md + a/b/c.md + a/b/d.md), the stored
+    # summary attached.
+    assert sub == [("a", 3, "A subtree.")]
+    assert files == [("S", "f.md", "F")]
+    assert total == 1
+    # One level down: a/b is a's direct subfolder with its own count.
+    sub2, _files2, _total2 = agent.group_folder_listing("S", "a", rows, {"a/b": "B subtree."})
+    assert sub2 == [("a/b", 2, "B subtree.")]
+
+
+def test_group_folder_listing_nested_level_counts_and_membership() -> None:
+    """One level down: ``a``'s direct subfolder is ``a/b`` (count 2),
+    its own direct file is ``a/e.md`` (``a/b/c.md`` is NOT a direct
+    file of ``a``) — membership is the folder_of rule, order is path
+    order."""
+    rows = [
+        ("a/b/c.md", "C"),
+        ("a/b/d.md", "D"),
+        ("a/e.md", "E"),
+    ]
+    sub, files, total = agent.group_folder_listing("S", "a", rows, {})
+    assert sub == [("a/b", 2, None)]
+    assert files == [("S", "a/e.md", "E")]
+    assert total == 1
+
+
+def test_group_folder_listing_file_path_is_not_a_folder() -> None:
+    """A document whose path is a prefix of NO other path is a file,
+    never a folder: ``ls`` of it must not list a subfolder (and the
+    ``path == folder`` count arm only fires for TRUE folders — a doc
+    sharing a real folder's name counts for that folder, the existence
+    rule intact)."""
+    rows = [
+        ("a.md", "A"),  # a file at the root, and a folder name? NO —
+        ("b/x.md", "X"),  # nothing starts with "a.md/"
+    ]
+    sub, files, total = agent.group_folder_listing("S", "", rows, {})
+    assert sub == [("b", 1, None)]  # "a.md" is NOT a subfolder
+    assert files == [("S", "a.md", "A")]  # b/x.md is NOT a direct root file
+    assert total == 1
+    # The path == folder arm: a doc named "a" under a real folder "a/".
+    rows2 = [("a", "FileA"), ("a/c.md", "C")]
+    sub2, files2, total2 = agent.group_folder_listing("S", "", rows2, {})
+    assert sub2 == [("a", 2, None)]  # the file "a" counts for folder "a"
+    assert files2 == [("S", "a", "FileA")]  # …and is a direct ROOT file
+    assert total2 == 1
+
+
+def test_group_folder_listing_caps_files_at_fifty_keeps_the_total() -> None:
+    """The cap: 51 direct files → 50 file lines + the PRE-cap total (51)
+    for the renderer's note; 50 files → 50 lines, no note material.
+    A 500-file folder costs 50 lines, never 500."""
+    rows51 = [(f"big/f{i:03d}.md", f"T{i}") for i in range(51)]
+    sub, files, total = agent.group_folder_listing("S", "big", rows51, {})
+    assert sub == []
+    assert total == 51
+    assert len(files) == 50
+    assert files[0] == ("S", "big/f000.md", "T0")
+    assert files[-1] == ("S", "big/f049.md", "T49")
+    rows50 = [(f"big/f{i:03d}.md", f"T{i}") for i in range(50)]
+    _sub, files50, total50 = agent.group_folder_listing("S", "big", rows50, {})
+    assert total50 == 50 and len(files50) == 50
+
+
+# ---------- the pinned drill-down templates (byte-for-byte) ----------
+
+
+def test_render_ls_top_template() -> None:
+    assert (
+        agent.render_ls_top(
+            [("Deployments", 3, None), ("Homelab", 5, "Home lab notes.")]
+        )
+        == "2 sources:\n\n"
+        "Deployments — 3 documents\n"
+        "Homelab — 5 documents\n"
+        "  Home lab notes."
+    )
+    assert agent.render_ls_top([]) == "0 sources:"
+
+
+def test_render_folder_listing_root_template() -> None:
+    assert (
+        agent.render_folder_listing(
+            "Homelab",
+            [("backups", 2, "Backup notes."), ("networking", 1, None)],
+            [("Homelab", "readme.md", "Readme")],
+            1,
+        )
+        == "Homelab — 1 documents, 2 folders:\n"
+        "\n"
+        "  backups/ — 2 documents: Backup notes.\n"
+        "  networking/ — 1 documents\n"
+        "\n"
+        "source: Homelab | path: readme.md | title: Readme"
+    )
+
+
+def test_render_folder_listing_empty_level_is_header_alone() -> None:
+    """A registered source with no documents: the header line alone —
+    the old ``0 documents:`` behavior preserved in spirit."""
+    assert agent.render_folder_listing("Homelab", [], [], 0) == (
+        "Homelab — 0 documents, 0 folders:"
+    )
+
+
+def test_render_folder_listing_subfolders_only_no_blank_trailer() -> None:
+    """Subfolders but no own files: header + blank + subfolder lines —
+    no trailing blank line, no file section."""
+    assert (
+        agent.render_folder_listing("S", [("a", 1, None)], [], 0)
+        == "S — 0 documents, 1 folders:\n\n  a/ — 1 documents"
+    )
+
+
+def test_render_folder_listing_cap_note_only_past_fifty() -> None:
+    """The note appears ONLY when the folder's own files outnumber the
+    cap: 51 → 50 lines + the deterministic grep-pointer note (the
+    ``…and 1 more…`` shape — unpluralized, the house pin); 50 → no
+    note."""
+    files51 = [("S", f"f{i:03d}.md", f"T{i}") for i in range(51)]
+    capped = files51[:50]
+    rendered = agent.render_folder_listing("S/big", [], capped, 51)
+    lines = rendered.splitlines()
+    assert lines[0] == "S/big — 51 documents, 0 folders:"
+    assert len(lines) == 1 + 1 + 50 + 1  # header, blank, 50 lines, note
+    assert lines[-1] == (
+        "…and 1 more documents in this folder — use grep (pattern) to "
+        "find a specific one."
+    )
+    files50 = [("S", f"f{i:03d}.md", f"T{i}") for i in range(50)]
+    rendered50 = agent.render_folder_listing("S/big", [], files50, 50)
+    assert rendered50.splitlines()[-1] == "source: S | path: f049.md | title: T49"
+    assert "more documents" not in rendered50
+
+
 # ---------- read: the canonical combined source/path form ----------
 
 
@@ -771,7 +1134,6 @@ def test_read_bare_source_name_refused_without_db(monkeypatch: pytest.MonkeyPatc
     no-document refusal (the argument echoed as passed), no DB lookup
     (NOT even the phase-72 candidate lookup — ``all_documents`` must
     not run either), nothing counted."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("Homelab", "a.md", "A")])
 
     def _boom(*_a: Any, **_k: Any) -> None:
         raise AssertionError(
@@ -1158,7 +1520,6 @@ def test_reading_an_already_read_doc_is_deduped(monkeypatch: pytest.MonkeyPatch)
 
 
 def test_unknown_tool_name_refused(monkeypatch: pytest.MonkeyPatch) -> None:
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [])
     holder = AgentHolder()
     llm = ScriptedLLM(
         [ToolCallPiece(id="call_1", name="delete_universe", arguments={"x": 1})],
@@ -1702,13 +2063,11 @@ def test_grep_counts_but_never_adds_context(monkeypatch: pytest.MonkeyPatch) ->
 
 
 def test_relist_executes_and_counts(monkeypatch: pytest.MonkeyPatch) -> None:
-    """Re-lists execute — a second ``ls`` in one turn returns the catalog
+    """Re-lists execute — a second ``ls`` in one turn returns the top
-    again and counts in ``tool_calls`` (no budget to exhaust)."""
+    level again and counts in ``tool_calls`` (no budget to exhaust)."""
-    catalog = [
+    monkeypatch.setattr(
-        ("Deployments", "backups.md", "Backup Strategy"),
+        agent, "ls_top", lambda db: [("Deployments", 1, None), ("Homelab", 1, None)]
-        ("Homelab", "aws-route53.md", "AWS Route53 Records"),
+    )
-    ]
-    monkeypatch.setattr(agent, "list_catalog", lambda db: catalog)
     holder = AgentHolder()
     llm = ScriptedLLM(
         [ToolCallPiece(id="call_1", name="ls", arguments={})],
@@ -1717,12 +2076,8 @@ def test_relist_executes_and_counts(monkeypatch: pytest.MonkeyPatch) -> None:
     )
     asyncio.run(_run(llm, holder, _settings()))
     assert holder.tool_calls == 2  # both re-lists executed and counted
-    listing = (
+    listing = "2 sources:\n\nDeployments — 1 documents\nHomelab — 1 documents"
-        "2 documents:\n"
+    # The answer request carries the listing a second time as a tool result.
-        "source: Deployments | path: backups.md | title: Backup Strategy\n"
-        "source: Homelab | path: aws-route53.md | title: AWS Route53 Records"
-    )
-    # The answer request carries the catalog a second time as a tool result.
     assert llm.requests[2][0][3]["content"] == listing  # first listing
     assert llm.requests[2][0][5]["content"] == listing  # the re-list
     assert llm.requests[2][1] == AGENT_TOOLS  # still offered (no budgets)
@@ -1758,8 +2113,8 @@ def test_always_ls_bounded_by_round_cap(monkeypatch: pytest.MonkeyPatch) -> None
     """A model that keeps calling ``ls`` gets exactly
     ``agent_max_rounds`` tool rounds, then one forced ``tools=None``
     request streams the answer — the cap is the only forced exit."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
+    monkeypatch.setattr(agent, "ls_top", lambda db: [("S", 1, None)])
-    listing = "1 documents:\nsource: S | path: a.md | title: A"
+    listing = "1 sources:\n\nS — 1 documents"
     holder = AgentHolder()
     llm = ScriptedLLM(
         [ToolCallPiece(id="call_1", name="ls", arguments={})],
@@ -1923,7 +2278,7 @@ def test_round_retried_before_first_piece(
     same messages: the stream carries a RetryPiece BEFORE the tool call,
     the tool executes, the final answer streams, and the per-call log line
     is still emitted exactly once (retries are invisible to the loop)."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
+    monkeypatch.setattr(agent, "ls_top", lambda db: [("S", 1, None)])
     holder = AgentHolder()
     llm = FailingLLM(
         [
@@ -1961,7 +2316,6 @@ def test_round_failure_after_first_piece_is_terminal(monkeypatch: pytest.MonkeyP
     the LLMError propagates out of ``run_agent``, no RetryPiece, no
     sleep, no second request, and the holder is untouched (the tool
     never ran)."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [])
     holder = AgentHolder()
     llm = FailingLLM(
         [([StreamPiece("content", "partial ")], LLMError("mid-stream drop"))]
@@ -1994,7 +2348,7 @@ def test_forced_final_no_tools_call_is_retried(monkeypatch: pytest.MonkeyPatch)
     """The forced final request (round cap reached) goes through the same
     retry rule: a failure before its first piece yields a RetryPiece and
     restarts with ``tools=None``; the answer from the retry streams."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
+    monkeypatch.setattr(agent, "ls_top", lambda db: [("S", 1, None)])
     holder = AgentHolder()
     llm = FailingLLM(
         [
@@ -2026,7 +2380,6 @@ def test_zero_retries_is_one_plain_attempt(monkeypatch: pytest.MonkeyPatch) -> N
     """The kill-switch path (``llm_retries=0``): a dead round raises
     immediately — one request, no RetryPiece, no sleep (pre-phase-67
     behavior)."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [])
     holder = AgentHolder()
     llm = FailingLLM([([], LLMError("connection refused"))])
     sleeps = _record_sleeps(monkeypatch)
@@ -2065,7 +2418,6 @@ def test_abandon_mid_retry_sleep_leaks_nothing(monkeypatch: pytest.MonkeyPatch)
         await asyncio.Event().wait()  # park until the abandon arrives
 
     monkeypatch.setattr(asyncio, "sleep", parking_sleep)
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [])
     holder = AgentHolder()
     llm = FailingLLM(
         [([], LLMError("endpoint down")), ([StreamPiece("content", "never")], None)]
@@ -2111,7 +2463,7 @@ def test_retries_are_invisible_to_the_round_cap(
     2, the retried first round and the second tool round fill the cap —
     the forced final follows the SECOND call, and the log lines read
     round=1/2 and round=2/2."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
+    monkeypatch.setattr(agent, "ls_top", lambda db: [("S", 1, None)])
     holder = AgentHolder()
     llm = FailingLLM(
         [
@@ -2364,7 +2716,7 @@ def test_scaffolding_round_with_tool_calls_needs_no_recovery(
     ran, and the policy keys on the no-calls exit only — no recovery (the
     next round is a normal tools-offered round carrying the tool
     history)."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
+    monkeypatch.setattr(agent, "ls_top", lambda db: [("S", 1, None)])
     holder = AgentHolder()
     llm = ScriptedLLM(
         [
@@ -2398,7 +2750,7 @@ def test_recovery_after_tool_rounds_keeps_the_history(
     keeps the SINGLE (folded) system message at the front and the tool
     history intact behind it — no second system message, no duplicated
     correction."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
+    monkeypatch.setattr(agent, "ls_top", lambda db: [("S", 1, None)])
     holder = AgentHolder()
     llm = ScriptedLLM(
         [ToolCallPiece(id="call_1", name="ls", arguments={})],
@@ -2423,7 +2775,7 @@ def test_recovery_after_tool_rounds_keeps_the_history(
     assert recovered[3] == {
         "role": "tool",
         "tool_call_id": "call_1",
-        "content": "1 documents:\nsource: S | path: a.md | title: A",
+        "content": "1 sources:\n\nS — 1 documents",
     }
     assert sum(1 for m in recovered if m["role"] == "system") == 1
     assert holder.scaffold_stripped == len(_INCIDENT_SPAN)
@@ -2436,7 +2788,7 @@ def test_forced_final_scaffolding_only_settles_malformed(
     scaffolding-only forced answer never reaches the user raw — the turn
     settles with :class:`MalformedReplyError` (the same terminal
     semantics; this turn used no recovery, so nothing is doubled up)."""
-    monkeypatch.setattr(agent, "list_catalog", lambda db: [("S", "a.md", "A")])
+    monkeypatch.setattr(agent, "ls_top", lambda db: [("S", 1, None)])
     holder = AgentHolder()
     llm = ScriptedLLM(
         [ToolCallPiece(id="call_1", name="ls", arguments={})],

tests/unit/test_folder_summaries.py

@@ -0,0 +1,628 @@
+"""Unit: folder summary storage + generator (phase 94, task 01).
+
+The prompt/grouping tests are pure (no DB): ``FOLDER_SUMMARY_MODE``
+system prompt, the ``folder_of`` / ``group_by_folder`` recursive-subtree
+concept, and the user-message cap with the shared ``[…truncated…]``
+marker. The generator tests run against the local compose Postgres
+(preferred — real upsert/prune on the ``folder_summaries`` table),
+skipping with clear instructions when the stack is not up — same
+pattern as ``test_overview.py``.
+"""
+from __future__ import annotations
+
+import asyncio
+import logging
+import uuid
+from datetime import UTC, datetime
+from typing import Any
+
+import pytest
+from sqlalchemy import text
+from sqlalchemy.orm import Session
+
+from app.config import Settings, get_settings
+from app.db import SessionLocal
+from app.models import Document, FolderSummary
+from app.rag.folder_summaries import (
+    FOLDER_HEADER_PREFIX,
+    FOLDER_SUMMARY_INSTRUCTION,
+    FOLDER_SUMMARY_MODE,
+    MIN_DOCS_PER_FOLDER,
+    SYSTEM_PROMPT,
+    build_folder_summary_prompt,
+    folder_of,
+    folder_summary_table_empty,
+    generate_folder_summaries,
+    group_by_folder,
+    summarize_folder,
+)
+from app.rag.llm import LLMError
+from app.rag.retriever import TRUNCATION_MARKER
+from tests.e2e.mock_llm import compose_answer
+
+REPLY = "Covers lab automation runbooks: inventories, playbooks, and schedules."
+
+
+class _FakeLLM:
+    """Duck-typed stand-in for ``LLMClient`` (``chat`` + ``settings``).
+
+    Records each ``(system, user)`` request and the ``model`` kwarg;
+    returns the canned reply, or raises — either a fixed exception or a
+    per-folder failure keyed on the user message's ``Folder: …`` header
+    (the per-folder fail-soft tests).
+    """
+
+    def __init__(
+        self,
+        reply: str = REPLY,
+        fail_folders: tuple[str, ...] = (),
+        fail: Exception | None = None,
+    ) -> None:
+        self._reply = reply
+        self._fail_folders = tuple(fail_folders)
+        self._fail = fail
+        self.settings = Settings(_env_file=None)  # pyright: ignore[reportCallIssue]
+        self.calls = 0
+        self.model: str | None = None
+        self.requests: list[tuple[str, str]] = []
+
+    async def chat(
+        self, messages: list[dict[str, str]], model: str | None = None
+    ) -> str:
+        self.calls += 1
+        self.model = model
+        system = messages[0]["content"]
+        user = messages[-1]["content"]
+        self.requests.append((system, user))
+        for folder in self._fail_folders:
+            if FOLDER_HEADER_PREFIX + folder in user:
+                raise LLMError(f"simulated lite-model failure for {folder}")
+        if self._fail is not None:
+            raise self._fail
+        return self._reply
+
+
+# ---------- folder_of ----------
+
+
+def test_folder_of_root_level_file_is_empty() -> None:
+    assert folder_of("a.md") == ""
+
+
+def test_folder_of_one_level() -> None:
+    assert folder_of("a/b.md") == "a"
+
+
+def test_folder_of_deep_path() -> None:
+    assert folder_of("a/b/c/d.md") == "a/b/c"
+
+
+def test_folder_of_iterating_walks_prefixes_to_root() -> None:
+    """Iterating ``folder_of`` over its own result walks the folder
+    prefixes nearest-first, ending at the root (the grouping walk)."""
+    folder = folder_of("a/b/c.md")
+    chain: list[str] = []
+    while folder:
+        chain.append(folder)
+        folder = folder_of(folder)
+    assert chain == ["a/b", "a"]  # plus the "" root the grouping adds
+
+
+# ---------- group_by_folder ----------
+
+
+def test_group_by_folder_root_file_lands_only_in_source_root() -> None:
+    rows = [("S", "top.md", "T", None)]
+    groups = group_by_folder(rows)
+    assert set(groups) == {("S", "")}
+    assert groups[("S", "")] == rows
+
+
+def test_group_by_folder_nested_multi_source_recursive_subtree() -> None:
+    """A doc under ``a/b/`` is present in the ``a``, ``a/b``, and ``""``
+    groups (recursive subtree — the ``ls`` count scope, one concept);
+    per source the candidates are ``""`` + every distinct folder
+    prefix; group lists keep the input (catalogue) order."""
+    rows = [
+        ("S", "a/b/c.md", "C", None),
+        ("S", "a/b/d.md", "D", None),
+        ("S", "a/x.md", "X", None),
+        ("S", "top.md", "T", None),
+        ("T", "a/b/e.md", "E", None),
+    ]
+    groups = group_by_folder(rows)
+    assert set(groups) == {
+        ("S", ""),
+        ("S", "a"),
+        ("S", "a/b"),
+        ("T", ""),
+        ("T", "a"),
+        ("T", "a/b"),
+    }
+    # The recursive-subtree concept: a/b/ docs in the a/, a/b/, and ""
+    # groups alike — exactly the set each level's ls count shows.
+    assert [r[1] for r in groups[("S", "a/b")]] == ["a/b/c.md", "a/b/d.md"]
+    assert [r[1] for r in groups[("S", "a")]] == ["a/b/c.md", "a/b/d.md", "a/x.md"]
+    assert [r[1] for r in groups[("S", "")]] == [
+        "a/b/c.md",
+        "a/b/d.md",
+        "a/x.md",
+        "top.md",
+    ]
+    # Multi-source: the same folder prefix under another source is a
+    # separate group (PK is (source, folder_path)).
+    assert [r[1] for r in groups[("T", "a/b")]] == ["a/b/e.md"]
+    assert [r[1] for r in groups[("T", "")]] == ["a/b/e.md"]
+    # Input (catalogue) order is preserved inside each group.
+    assert [r[2] for r in groups[("S", "")]] == ["C", "D", "X", "T"]
+
+
+def test_group_by_folder_single_doc_folder_is_a_group_too() -> None:
+    """Grouping is pure subtree membership (≥ 1 docs): the ≥ 2 rule is
+    the GENERATOR's (the recursive count below the minimum yields no
+    row — pinned by the generator tests, not the grouping)."""
+    rows = [("S", "a/only.md", "O", None)]
+    groups = group_by_folder(rows)
+    assert len(groups[("S", "a")]) == 1  # present, but below the minimum
+
+
+def test_group_by_folder_doc_path_equal_to_a_folder_prefix_counts_for_it() -> None:
+    """The count rule's ``path == folder`` arm: a document whose path
+    IS one of the source's folder prefixes (a file sharing its name
+    with a directory) belongs to that folder's group too — the grouping
+    stays EXACTLY the set the ``ls`` count rule counts (path equal or
+    starting with ``folder + "/"``), while the returned keys remain the
+    true folder prefixes only (no file-path keys)."""
+    rows = [
+        ("S", "a/b", "B", None),  # a file named "b" ... (its path is a folder prefix)
+        ("S", "a/b/c.md", "C", None),  # ... and a real folder "a/b/" holding a doc
+        ("S", "a/x.md", "X", None),
+    ]
+    groups = group_by_folder(rows)
+    assert set(groups) == {("S", ""), ("S", "a"), ("S", "a/b")}, (
+        "the keys stay the true folder prefixes — the file's own path adds no key"
+    )
+    assert [r[1] for r in groups[("S", "a/b")]] == ["a/b", "a/b/c.md"]
+    assert [r[1] for r in groups[("S", "a")]] == ["a/b", "a/b/c.md", "a/x.md"]
+    assert [r[1] for r in groups[("S", "")]] == ["a/b", "a/b/c.md", "a/x.md"]
+
+
+def test_group_by_folder_plain_file_path_is_not_a_group_key() -> None:
+    """A file path that is NO folder prefix (no doc under it) adds no
+    group key of its own — the ``path == folder`` arm only fires when
+    the path really is a prefix of the catalogue."""
+    rows = [("S", "top.md", "T", None), ("S", "a/one.md", "O", None)]
+    groups = group_by_folder(rows)
+    assert set(groups) == {("S", ""), ("S", "a")}
+    assert "top.md" not in [folder for _source, folder in groups]
+
+
+# ---------- build_folder_summary_prompt: system ----------
+
+
+def test_system_prompt_has_marker_and_locked_instruction() -> None:
+    assert SYSTEM_PROMPT.startswith(FOLDER_SUMMARY_MODE)
+    assert FOLDER_SUMMARY_INSTRUCTION in SYSTEM_PROMPT
+    for fragment in (
+        "1-3 sentence",
+        "plain-text summary",
+        "natural language",
+        "Do not use markdown",
+        "not in the list",
+    ):
+        assert fragment in SYSTEM_PROMPT
+    system, _ = build_folder_summary_prompt("S", "a/b", [])
+    assert system == SYSTEM_PROMPT
+    assert FOLDER_SUMMARY_MODE in system  # the marker the E2E mock keys on
+
+
+# ---------- build_folder_summary_prompt: user ----------
+
+
+def test_user_prompt_header_names_the_folder() -> None:
+    """The first line is the ``FOLDER_HEADER_PREFIX`` header the E2E
+    mock parses: ``<source>`` for the root, ``<source>/<folder_path>``
+    for a folder."""
+    _, user = build_folder_summary_prompt("Homelab", "deployments/ansible", [])
+    assert user == FOLDER_HEADER_PREFIX + "Homelab/deployments/ansible"
+    _, user = build_folder_summary_prompt("Homelab", "", [])
+    assert user == FOLDER_HEADER_PREFIX + "Homelab"
+
+
+def test_user_lines_carry_path_title_and_first_summary_line() -> None:
+    docs = [
+        ("S", "a/b/one.md", "One", "First lead.\nSecond line.\nSource: S/a/b/one.md"),
+        ("S", "a/b/two.md", "Two", None),
+    ]
+    system, user = build_folder_summary_prompt("S", "a/b", docs)
+    assert system == SYSTEM_PROMPT
+    assert user == (
+        "Folder: S/a/b\n"
+        "a/b/one.md — One — First lead.\n"
+        "a/b/two.md — Two"
+    )
+
+
+def test_user_line_omits_summary_field_when_absent_or_blank() -> None:
+    docs = [
+        ("S", "a/x.md", "X", None),
+        ("S", "a/y.md", "Y", "  \n\t "),
+    ]
+    _, user = build_folder_summary_prompt("S", "a", docs)
+    assert user == "Folder: S/a\na/x.md — X\na/y.md — Y"
+    assert " — " in user  # the path — title join only
+    assert not any(line.endswith(" — ") for line in user.splitlines())
+
+
+def test_user_line_uses_only_first_summary_line() -> None:
+    docs = [
+        ("S", "a/x.md", "X", "First line.\nSecond line.\nSource: S/a/x.md"),
+    ]
+    _, user = build_folder_summary_prompt("S", "a", docs)
+    assert user == "Folder: S/a\na/x.md — X — First line."
+    assert "Second line" not in user
+    assert "Source:" not in user
+
+
+def test_user_prompt_truncated_with_marker_when_over_custom_cap() -> None:
+    docs = [("S", f"a/f{i}.md", f"T{i}", None) for i in range(10)]
+    _, full = build_folder_summary_prompt("S", "a", docs, max_chars=10_000)
+    cap = 30
+    _, user = build_folder_summary_prompt("S", "a", docs, max_chars=cap)
+    assert user == full[:cap] + "\n" + TRUNCATION_MARKER
+    assert user.endswith(TRUNCATION_MARKER)
+    assert len(user) > cap  # the marker makes the cut visible past the cap
+
+
+def test_user_prompt_at_exact_cap_not_truncated() -> None:
+    docs = [("S", "a/x.md", "X", None)]  # "Folder: S/a\na/x.md — X" = 22 chars
+    _, user = build_folder_summary_prompt("S", "a", docs, max_chars=22)
+    assert user == "Folder: S/a\na/x.md — X"
+    assert TRUNCATION_MARKER not in user
+
+
+def test_user_prompt_truncated_at_default_cap() -> None:
+    """No explicit cap → ``BOR_FOLDER_SUMMARY_INPUT_MAX_CHARS`` (read
+    from the live settings, so the test holds for any configured
+    value)."""
+    cap = get_settings().folder_summary_input_max_chars
+    docs = [("S", f"a/f{i}.md", "T", None) for i in range(3_000)]
+    _, user = build_folder_summary_prompt("S", "a", docs)
+    assert user.endswith(TRUNCATION_MARKER)
+    body = user.removesuffix("\n" + TRUNCATION_MARKER)
+    assert len(body) == cap  # cut exactly at the cap, marker on its own line
+    assert "f2999.md" not in body  # the overflow never reaches the model
+
+
+# ---------- summarize_folder ----------
+
+
+# ---------- the E2E mock's FOLDER_SUMMARY_MODE branch ----------
+
+
+def _mock_body(system: str, user: str) -> dict[str, Any]:
+    """A minimal chat-completion body for the mock's ``compose_answer``."""
+    return {"messages": [
+        {"role": "system", "content": system},
+        {"role": "user", "content": user},
+    ]}
+
+
+def test_mock_returns_canned_folder_summary_naming_the_folder() -> None:
+    """The deterministic E2E mock keys on the ``FOLDER_SUMMARY_MODE``
+    marker in the system prompt and returns the canned one-liner naming
+    the folder from the ``Folder: …`` header — driven through the
+    GENERATOR's real prompt, so the two can never drift (the drill-down
+    E2E asserts on this exact template)."""
+    system, user = build_folder_summary_prompt(
+        "Homelab", "deployments/ansible",
+        [("Homelab", "deployments/ansible/lab-inventory.md", "Lab Inventory", None)],
+    )
+    assert compose_answer(_mock_body(system, user)) == (
+        "Fixture folder summary for Homelab/deployments/ansible."
+    )
+    # The source-root row names the source itself.
+    system, user = build_folder_summary_prompt("Homelab", "",
+                                               [("Homelab", "top.md", "Top", None)])
+    assert compose_answer(_mock_body(system, user)) == (
+        "Fixture folder summary for Homelab."
+    )
+
+
+def test_mock_folder_marker_is_not_shadowed_by_the_summary_branch() -> None:
+    """``FOLDER_SUMMARY_MODE`` contains ``SUMMARY_MODE`` as a substring —
+    the mock must check the folder branch FIRST, or every folder call
+    would land in the document-summary digest (regression pin)."""
+    system, user = build_folder_summary_prompt(
+        "S", "a", [("S", "a/x.md", "X", None)]
+    )
+    assert "SUMMARY_MODE" in system  # the shadowing hazard is real
+    answer = compose_answer(_mock_body(system, user))
+    assert answer == "Fixture folder summary for S/a."
+    assert not answer.startswith("This document covers")
+
+
+def test_summarize_folder_happy_path_returns_trimmed_text() -> None:
+    docs = [("S", "a/x.md", "X", None)]
+    llm = _FakeLLM(reply=f"  {REPLY}  \n")
+    out = asyncio.run(summarize_folder("S", "a", docs, llm))
+    assert out == REPLY  # the model's text, trimmed
+    assert llm.calls == 1
+
+
+def test_summarize_folder_calls_the_configured_summary_model_with_marker() -> None:
+    docs = [("S", "a/x.md", "X", "X lead.")]
+    llm = _FakeLLM()
+    asyncio.run(summarize_folder("S", "a", docs, llm))
+    assert llm.model == llm.settings.llm_summary_model  # the ``lite`` default
+    assert llm.model == "lite"
+    system, user = llm.requests[0]
+    assert FOLDER_SUMMARY_MODE in system
+    assert user.startswith(FOLDER_HEADER_PREFIX + "S/a")
+    assert "a/x.md — X — X lead." in user
+
+
+def test_summarize_folder_empty_reply_raises_llm_error() -> None:
+    docs = [("S", "a/x.md", "X", None)]
+    for reply in ("", "   \n\t "):
+        llm = _FakeLLM(reply=reply)
+        with pytest.raises(LLMError, match="empty content for S/a"):
+            asyncio.run(summarize_folder("S", "a", docs, llm))
+
+
+def test_summarize_folder_error_propagates() -> None:
+    docs = [("S", "a/x.md", "X", None)]
+    llm = _FakeLLM(fail=LLMError("simulated transport failure"))
+    with pytest.raises(LLMError, match="simulated transport failure"):
+        asyncio.run(summarize_folder("S", "a", docs, llm))
+
+
+# ---------- generate_folder_summaries (real Postgres) ----------
+
+
+def _add_doc(
+    db: Session, source: str, path: str, title: str, summary: str | None = None
+) -> Document:
+    doc = Document(
+        id=uuid.uuid4(),
+        source=source,
+        path=path,
+        full_path=f"/tmp/{path}",
+        title=title,
+        content="body",
+        content_hash="0" * 64,
+        summary=summary,
+    )
+    db.add(doc)
+    db.commit()
+    return doc
+
+
+def _truncate(db: Session) -> None:
+    db.execute(text("TRUNCATE chunks, documents"))
+    db.execute(text("DELETE FROM folder_summaries"))
+    db.commit()
+
+
+def _rows(db: Session) -> dict[tuple[str, str], str]:
+    """The stored folder summaries: ``{(source, folder_path): summary}``."""
+    result = db.execute(
+        text("SELECT source, folder_path, summary FROM folder_summaries")
+    ).all()
+    return {(source, folder_path): summary for source, folder_path, summary in result}
+
+
+def _seed_catalogue(db: Session) -> None:
+    """The shared catalogue: FSU has four docs in three candidate
+    folders (root 4, a 3, a/b 2 — all ≥ the minimum); FSU-solo has one
+    doc (its root folder is below the minimum — no row, no call)."""
+    _add_doc(db, "FSU", "a/b/one.md", "One", "One lead.\nSource: FSU/a/b/one.md")
+    _add_doc(db, "FSU", "a/b/two.md", "Two")
+    _add_doc(db, "FSU", "a/three.md", "Three")
+    _add_doc(db, "FSU", "root.md", "Root")
+    _add_doc(db, "FSU-solo", "solo.md", "Solo")
+
+
+@pytest.fixture()
+def clean_tables(db: Session):
+    _truncate(db)
+    yield
+    _truncate(db)
+
+
+def test_generate_happy_path_upserts_every_candidate_folder(
+    db: Session, clean_tables, caplog: pytest.LogCaptureFixture
+) -> None:
+    """Every folder with ≥ 2 recursive docs gets a row (the source root
+    row included — ``folder_path = ''``); single-doc folders get none;
+    rows are stamped fresh; the stats dict and the log line are right;
+    folders are processed in deterministic (source, folder_path) order."""
+    _seed_catalogue(db)
+    llm = _FakeLLM()
+    with caplog.at_level(logging.INFO, logger="app.rag.folder_summaries"):
+        stats = asyncio.run(generate_folder_summaries(db, llm))
+    assert stats == {"generated": 3, "failed": 0, "pruned": 0}
+    assert llm.calls == 3, "one lite call per candidate folder (the solo folder: none)"
+
+    stored = _rows(db)
+    assert set(stored) == {("FSU", ""), ("FSU", "a"), ("FSU", "a/b")}
+    assert all(summary == REPLY for summary in stored.values())
+    assert ("FSU-solo", "") not in stored, (
+        "a single-doc folder is fully described by its one file line — no row"
+    )
+
+    row = db.get(FolderSummary, ("FSU", "a/b"))
+    assert row is not None
+    assert row.summary == REPLY
+    assert row.updated_at is not None
+    age = datetime.now(UTC) - row.updated_at
+    assert age.total_seconds() < 300, "updated_at must be a fresh UTC timestamp"
+
+    # Deterministic (source, folder_path) order — root before the
+    # nested folders, one header per call.
+    assert [user.splitlines()[0] for _s, user in llm.requests] == [
+        "Folder: FSU",
+        "Folder: FSU/a",
+        "Folder: FSU/a/b",
+    ]
+    # The recursive-subtree input: the a/ prompt carries a/b's docs too.
+    a_prompt = llm.requests[1][1]
+    assert "a/b/one.md — One — One lead." in a_prompt
+    assert "a/three.md — Three" in a_prompt
+    assert "root.md — Root" not in a_prompt
+
+    assert (
+        "folder_summaries: generated=3 failed=0 pruned=0" in caplog.text
+    ), "the stats line must be greppable (PLAN §9 ample logging)"
+
+
+def test_generate_per_folder_fail_soft_keeps_previous_and_lands_others(
+    db: Session, clean_tables, caplog: pytest.LogCaptureFixture
+) -> None:
+    """One folder's lite failure is logged and counted, its PREVIOUS
+    row is kept (an old summary is better than none), and the remaining
+    folders still land — a lite outage never fails the sync."""
+    _seed_catalogue(db)
+    db.add(FolderSummary(source="FSU", folder_path="a/b", summary="old summary"))
+    db.commit()
+    llm = _FakeLLM(fail_folders=("FSU/a/b",))
+    with caplog.at_level(logging.ERROR, logger="app.rag.folder_summaries"):
+        stats = asyncio.run(generate_folder_summaries(db, llm))
+    assert stats == {"generated": 2, "failed": 1, "pruned": 0}
+    assert llm.calls == 3  # the failing folder was attempted too
+
+    stored = _rows(db)
+    assert stored[("FSU", "a/b")] == "old summary", (
+        "the previous row survives the per-folder failure"
+    )
+    assert stored[("FSU", "")] == REPLY and stored[("FSU", "a")] == REPLY, (
+        "the other folders still land"
+    )
+    assert "folder summary failed for FSU/a/b" in caplog.text
+    assert "simulated lite-model failure for FSU/a/b" in caplog.text
+
+
+def test_generate_per_folder_fail_soft_without_previous_row_creates_nothing(
+    db: Session, clean_tables
+) -> None:
+    _seed_catalogue(db)
+    llm = _FakeLLM(fail_folders=("FSU/a/b",))
+    stats = asyncio.run(generate_folder_summaries(db, llm))
+    assert stats["failed"] == 1
+    stored = _rows(db)
+    assert ("FSU", "a/b") not in stored, "no row must be invented for a failed folder"
+    assert ("FSU", "") in stored and ("FSU", "a") in stored
+
+
+def test_generate_prunes_stale_rows_and_keeps_live_ones(db: Session, clean_tables) -> None:
+    """Rows for folders that dropped below 2 recursive docs are deleted
+    (pruned/renamed — the summary would go stale); rows for folders
+    that still qualify persist (an unchanged folder's summary is still
+    true — regenerated in place)."""
+    _seed_catalogue(db)
+    # A stale row for a folder no longer in the catalogue (3→1 docs /
+    # renamed away) + a live row with old content.
+    db.add(FolderSummary(source="FSU", folder_path="gone/old", summary="stale"))
+    db.add(FolderSummary(source="FSU", folder_path="a", summary="old a summary"))
+    db.add(FolderSummary(source="FSU-solo", folder_path="", summary="solo stale"))
+    db.commit()
+    stats = asyncio.run(generate_folder_summaries(db, _FakeLLM()))
+    assert stats["pruned"] == 2  # gone/old + the FSU-solo root (1 doc)
+
+    stored = _rows(db)
+    assert ("FSU", "gone/old") not in stored, "the stale folder row must be pruned"
+    assert ("FSU-solo", "") not in stored, (
+        "a folder that dropped below 2 docs loses its row"
+    )
+    assert ("FSU", "a") in stored, "the still-qualifying folder keeps its row"
+    assert stored[("FSU", "a")] == REPLY  # regenerated, not stale
+    assert stored[("FSU", "")] == REPLY and stored[("FSU", "a/b")] == REPLY
+
+
+def test_generate_skip_is_a_full_noop(db: Session, clean_tables) -> None:
+    """``skip=True`` (the ``--limit`` debug run): the LLM is never
+    called, no rows are touched, zero stats."""
+    _seed_catalogue(db)
+    db.add(FolderSummary(source="FSU", folder_path="", summary="existing"))
+    db.commit()
+    llm = _FakeLLM()
+    stats = asyncio.run(generate_folder_summaries(db, llm, skip=True))
+    assert stats == {"generated": 0, "failed": 0, "pruned": 0}
+    assert llm.calls == 0
+    assert _rows(db) == {("FSU", ""): "existing"}
+
+
+def test_generate_empty_kb_prunes_every_row(db: Session, clean_tables) -> None:
+    """No documents → no candidate folders → every stored row is
+    pruned, with zero wasted lite calls."""
+    db.add(FolderSummary(source="FSU", folder_path="", summary="old"))
+    db.add(FolderSummary(source="FSU", folder_path="a/b", summary="old"))
+    db.commit()
+    llm = _FakeLLM()
+    stats = asyncio.run(generate_folder_summaries(db, llm))
+    assert stats == {"generated": 0, "failed": 0, "pruned": 2}
+    assert llm.calls == 0
+    assert _rows(db) == {}
+
+
+def test_generate_summarizes_folder_whose_prefix_is_also_a_doc_path(
+    db: Session, clean_tables
+) -> None:
+    """The ``path == folder`` arm end to end: a file sharing its name
+    with a directory counts toward the folder's recursive count (2
+    docs → the folder is summarized, and BOTH docs are in its prompt).
+    """
+    _add_doc(db, "FSU", "a/b", "B")  # a file named "b" (its path is a prefix)
+    _add_doc(db, "FSU", "a/b/c.md", "C")  # and a real folder "a/b/"
+    llm = _FakeLLM()
+    stats = asyncio.run(generate_folder_summaries(db, llm))
+    assert stats["generated"] == 3  # root (2), a (2), a/b (2) — all ≥ the minimum
+    stored = _rows(db)
+    assert set(stored) == {("FSU", ""), ("FSU", "a"), ("FSU", "a/b")}
+    a_b_prompt = [
+        user for _system, user in llm.requests if user.startswith("Folder: FSU/a/b\n")
+    ][0]
+    assert "a/b — B" in a_b_prompt
+    assert "a/b/c.md — C" in a_b_prompt
+
+
+def test_generate_only_flushes_caller_commits(db: Session, clean_tables) -> None:
+    """The generator only flushes — the sync path owns the transaction
+    (the phase-53 ``bump_sources_version`` convention): the catalogue
+    is committed (the real sync path commits the import before the
+    summary hooks run), but a second session sees the generator's rows
+    as NOTHING until the CALLER commits — and sees them after."""
+    _add_doc(db, "FSU", "x/y/one.md", "One")
+    _add_doc(db, "FSU", "x/y/two.md", "Two")
+    stats = asyncio.run(generate_folder_summaries(db, _FakeLLM()))
+    assert stats["generated"] == 3  # root + x + x/y — all 2 recursive docs
+
+    with SessionLocal() as other:
+        n = other.scalar(
+            text("SELECT count(*) FROM folder_summaries WHERE source = 'FSU'")
+        )
+        assert n == 0, "unflushed-by-caller rows must not be visible yet"
+
+    db.commit()
+    with SessionLocal() as other:
+        n = other.scalar(
+            text("SELECT count(*) FROM folder_summaries WHERE source = 'FSU'")
+        )
+        assert n == 3, "the caller's commit makes the flushed rows durable"
+
+    assert MIN_DOCS_PER_FOLDER == 2  # the ≥ 2 scope rule, pinned by name
+
+
+def test_folder_summary_table_empty_gate(db: Session, clean_tables) -> None:
+    """The sync-path gate probe (phase 94, task 02): empty → True
+    (the first full sync after migration 0017 must still generate),
+    one row → False (a populated table waits for a KB change)."""
+    assert folder_summary_table_empty(db) is True  # the truncated table
+    _add_doc(db, "FSU", "a/one.md", "One")
+    _add_doc(db, "FSU", "a/two.md", "Two")
+    asyncio.run(generate_folder_summaries(db, _FakeLLM()))
+    db.commit()
+    assert folder_summary_table_empty(db) is False  # rows landed
+    db.execute(text("DELETE FROM folder_summaries"))
+    db.commit()
+    assert folder_summary_table_empty(db) is True  # emptied again

tests/unit/test_mock_tool_flow.py

@@ -4,12 +4,18 @@ The mock (``tests/e2e/mock_llm.py``) classifies marker requests
 statelessly into one step of the agent tool flow. This file pins the
 classification at unit speed — no Playwright, no LLM process:
 
-* the phase-37 SINGLE-READ flow (``TOOLS_TRIGGER`` only) stays
+* the phase-37/94 SINGLE-READ flow (``TOOLS_TRIGGER`` only): list (the
-  byte-identical: list → read (first catalog line, ``call_1``) → answer;
+  top-level source listing) → drill (``ls`` scoped to the first source
-* the phase-45 MULTI-READ flow (``TOOLS_TRIGGER`` + ``MULTI_READ_TRIGGER``)
+  — phase 94: the top level carries sources only, so the flow drills
-  classifies by the count of ``tool``-role read results: list → read #1
+  one level for the file lines) → read (first file line, the combined
-  (``call_1``) → read #2 (second catalog line, ``call_2``) → the
+  ``source/path``) → answer;
-  byte-stable ``multi_answer`` naming both read paths.
+* the phase-45 MULTI-READ flow (``TOOLS_TRIGGER`` +
+  ``MULTI_READ_TRIGGER``) classifies by the count of ``tool``-role read
+  results: list → drill → read #1 (first file line) → read #2 (second
+  file line) → the byte-stable ``multi_answer`` naming both read paths;
+* the degenerate empty-KB case: every listed source already drilled
+  with no file lines → the flow falls back to the re-list loop (the
+  round cap settles it — the phase-70 empty-catalog behavior).
 """
 from __future__ import annotations
 
@@ -36,28 +42,50 @@ SYSTEM_LOW = "<relevance>LOW</relevance>\n"
 #: the phase-70 harness-aligned names).
 TOOLS = [{"type": "function", "function": {"name": "ls"}}]
 
-#: The agent's ``ls`` output for a two-document KB
+#: The agent's drill-down ``ls`` output for a two-source KB
-#: (``app/rag/agent.py`` ``_execute_tool``): one
+#: (``app/rag/agent.py`` ``render_ls_top`` / ``render_folder_listing``,
-#: ``source: X | path: Y | title: Z`` line per document (phase 63: labeled,
+#: phase 94): the top level lists the registered sources (registry
-#: unambiguous fields), ``(source, path)`` order.
+#: order, recursive counts — no file lines); the folder level carries
-CATALOG_2 = (
+#: the file lines (``source: X | path: Y | title: Z`` — the phase-63
-    "2 documents:\n"
+#: labeled fields, unchanged), ``path`` order.
-    "source: Deployments | path: example-record-file.json | title: Example Record File\n"
+TOP_LEVEL_2 = (
-    "source: Homelab | path: aws-route53.md | title: AWS Route 53 Notes"
+    "2 sources:\n"
+    "\n"
+    "Deployments — 1 documents\n"
+    "Homelab — 1 documents"
 )
 
-CATALOG_1 = (
+#: The first source's root folder: one file line (the single-read
-    "1 documents:\n"
+#: flow's read target).
+FOLDER_DEPLOYMENTS = (
+    "Deployments — 1 documents, 0 folders:\n"
+    "\n"
     "source: Deployments | path: example-record-file.json | title: Example Record File"
 )
 
-CATALOG_3 = (
+#: Two file lines in the first source (the multi-read flow's reads).
-    "3 documents:\n"
+FOLDER_DEPLOYMENTS_2 = (
+    "Deployments — 2 documents, 0 folders:\n"
+    "\n"
+    "source: Deployments | path: aaa.md | title: AAA\n"
+    "source: Deployments | path: bbb.md | title: BBB"
+)
+
+#: Three file lines in the first source (the listing-order pin: read
+#: #2 is the SECOND line, not the last).
+FOLDER_DEPLOYMENTS_3 = (
+    "Deployments — 3 documents, 0 folders:\n"
+    "\n"
     "source: Deployments | path: aaa.md | title: AAA\n"
     "source: Deployments | path: bbb.md | title: BBB\n"
-    "source: Homelab | path: ccc.md | title: CCC"
+    "source: Deployments | path: ccc.md | title: CCC"
 )
 
+#: Empty folder levels (a registered source with no documents — the
+#: header line alone; the drill's degenerate arm).
+FOLDER_DEPLOYMENTS_EMPTY = "Deployments — 0 documents, 0 folders:"
+FOLDER_HOMELAB_EMPTY = "Homelab — 0 documents, 0 folders:"
+
 DOC1_SP = "Deployments/example-record-file.json"
 DOC1_CONTENT = (
     "The record file keeps every hosted zone record — first line is longer "
@@ -122,10 +150,39 @@ def test_single_flow_list_step() -> None:
     assert _tool_flow(_body(SINGLE_USER)) == ("list", "", "")
 
 
-def test_single_flow_read_step_first_catalog_line() -> None:
+def test_single_flow_drill_step_after_top_level() -> None:
-    flow = _tool_flow(_body(SINGLE_USER, (CATALOG_3,)))
+    # Phase 94: the top level lists SOURCES only — the flow drills one
-    # The FIRST listing line (Deployments/aaa.md), labeled fields.
+    # level into the FIRST source (listing order = registry order).
-    assert flow == ("read", "Deployments", "aaa.md", "call_1")
+    flow = _tool_flow(_body(SINGLE_USER, (TOP_LEVEL_2,)))
+    assert flow == ("drill", "Deployments", "call_1")
+
+
+def test_single_flow_drill_skips_already_drilled_source() -> None:
+    # The first source's folder level is already in the messages (an
+    # empty listing — header only, no file lines): the drill proceeds
+    # to the NEXT un-drilled source.
+    flow = _tool_flow(_body(SINGLE_USER, (TOP_LEVEL_2, FOLDER_DEPLOYMENTS_EMPTY)))
+    assert flow == ("drill", "Homelab", "call_1")
+
+
+def test_single_flow_all_sources_drilled_empty_falls_back_to_list() -> None:
+    # Degenerate: every listed source already drilled, no file lines
+    # anywhere — the flow falls back to the re-list loop (settled at the
+    # round cap, the phase-70 empty-catalog behavior).
+    flow = _tool_flow(
+        _body(
+            SINGLE_USER,
+            (TOP_LEVEL_2, FOLDER_DEPLOYMENTS_EMPTY, FOLDER_HOMELAB_EMPTY),
+        )
+    )
+    assert flow == ("list", "", "")
+
+
+def test_single_flow_read_step_first_file_line() -> None:
+    # The folder level reached: the FIRST file line (Deployments/aaa.md),
+    # labeled fields, the combined ``source/path`` join.
+    flow = _tool_flow(_body(SINGLE_USER, (TOP_LEVEL_2, FOLDER_DEPLOYMENTS_2)))
+    assert flow == ("read", "Deployments", "aaa.md", "call_2")
 
 
 def test_read_step_nested_path_stays_intact() -> None:
@@ -133,19 +190,20 @@ def test_read_step_nested_path_stays_intact() -> None:
     # ``source/path — title`` + ``rpartition("/")`` parse misread the
     # split (``source=brain-of-reese-main/homelab``). The labeled fields
     # recover the nested path intact, however deep.
-    catalog = (
+    listing = (
-        "1 documents:\n"
+        "brain-of-reese-main — 1 documents, 0 folders:\n"
+        "\n"
         "source: brain-of-reese-main | path: homelab/aws-route53.md | title: aws-route53"
     )
-    flow = _tool_flow(_body(SINGLE_USER, (catalog,)))
+    flow = _tool_flow(_body(SINGLE_USER, (TOP_LEVEL_2, listing)))
-    assert flow == ("read", "brain-of-reese-main", "homelab/aws-route53.md", "call_1")
+    assert flow == ("read", "brain-of-reese-main", "homelab/aws-route53.md", "call_2")
 
 
 def test_single_flow_answer_step_with_tools_offered() -> None:
     # Phase 45: the round cap keeps the tools offered until it is hit —
     # the answer step fires regardless of the ``tools`` parameter.
     flow = _tool_flow(
-        _body(SINGLE_USER, (CATALOG_2, _read_result(DOC1_SP, DOC1_CONTENT)))
+        _body(SINGLE_USER, (TOP_LEVEL_2, FOLDER_DEPLOYMENTS, _read_result(DOC1_SP, DOC1_CONTENT)))
     )
     assert flow == ("answer", DOC1_SP, DOC1_CONTENT)
 
@@ -154,7 +212,7 @@ def test_single_flow_answer_step_without_tools() -> None:
     flow = _tool_flow(
         _body(
             SINGLE_USER,
-            (CATALOG_2, _read_result(DOC1_SP, DOC1_CONTENT)),
+            (TOP_LEVEL_2, FOLDER_DEPLOYMENTS, _read_result(DOC1_SP, DOC1_CONTENT)),
             tools=None,
         )
     )
@@ -184,22 +242,39 @@ def test_multi_flow_list_step() -> None:
     assert _tool_flow(_body(MULTI_USER)) == ("list", "", "")
 
 
+def test_multi_flow_drill_step_after_top_level() -> None:
+    # Phase 94: the top level lists SOURCES only — the multi flow drills
+    # too, before its first read.
+    flow = _tool_flow(_body(MULTI_USER, (TOP_LEVEL_2,)))
+    assert flow == ("drill", "Deployments", "call_1")
+
+
 def test_multi_flow_read_first_step() -> None:
-    flow = _tool_flow(_body(MULTI_USER, (CATALOG_2,)))
+    flow = _tool_flow(_body(MULTI_USER, (TOP_LEVEL_2, FOLDER_DEPLOYMENTS)))
-    assert flow == ("read", DOC1_SP.split("/", 1)[0], DOC1_SP.rsplit("/", 1)[1], "call_1")
+    assert flow == ("read", DOC1_SP.split("/", 1)[0], DOC1_SP.rsplit("/", 1)[1], "call_2")
 
 
 def test_multi_flow_read_second_step_skips_already_read() -> None:
-    flow = _tool_flow(_body(MULTI_USER, (CATALOG_2, _read_result(DOC1_SP, DOC1_CONTENT))))
+    flow = _tool_flow(
-    # The second catalog line — the first line differing from DOC1.
+        _body(
-    assert flow == ("read", "Homelab", "aws-route53.md", "call_2")
+            MULTI_USER,
+            (TOP_LEVEL_2, FOLDER_DEPLOYMENTS_2, _read_result("Deployments/aaa.md", DOC1_CONTENT)),
+        )
+    )
+    # The second file line — the first line differing from the read doc.
+    assert flow == ("read", "Deployments", "bbb.md", "call_3")
 
 
 def test_multi_flow_read_second_is_listing_order_not_last() -> None:
-    # Three-doc catalog, first doc read: read #2 is the SECOND line
+    # Three-file listing, first file read: read #2 is the SECOND line
     # (Deployments/bbb.md), not the last one.
-    flow = _tool_flow(_body(MULTI_USER, (CATALOG_3, _read_result("Deployments/aaa.md", "x"))))
+    flow = _tool_flow(
-    assert flow == ("read", "Deployments", "bbb.md", "call_2")
+        _body(
+            MULTI_USER,
+            (TOP_LEVEL_2, FOLDER_DEPLOYMENTS_3, _read_result("Deployments/aaa.md", "x")),
+        )
+    )
+    assert flow == ("read", "Deployments", "bbb.md", "call_3")
 
 
 def test_multi_flow_answer_step_names_both_paths() -> None:
@@ -207,7 +282,8 @@ def test_multi_flow_answer_step_names_both_paths() -> None:
         _body(
             MULTI_USER,
             (
-                CATALOG_2,
+                TOP_LEVEL_2,
+                FOLDER_DEPLOYMENTS_2,
                 _read_result(DOC1_SP, DOC1_CONTENT),
                 _read_result(DOC2_SP, DOC2_CONTENT),
             ),
@@ -227,7 +303,8 @@ def test_multi_flow_answer_step_without_tools_offered() -> None:
         _body(
             MULTI_USER,
             (
-                CATALOG_2,
+                TOP_LEVEL_2,
+                FOLDER_DEPLOYMENTS_2,
                 _read_result(DOC1_SP, DOC1_CONTENT),
                 _read_result(DOC2_SP, DOC2_CONTENT),
             ),
@@ -238,11 +315,11 @@ def test_multi_flow_answer_step_without_tools_offered() -> None:
     assert flow[0] == "multi_answer"
 
 
-def test_multi_flow_one_document_catalog_degenerates_to_single_answer() -> None:
+def test_multi_flow_one_file_listing_degenerates_to_single_answer() -> None:
     # Nothing second to read — the single-read answer shape, quoting the
     # only read result.
     flow = _tool_flow(
-        _body(MULTI_USER, (CATALOG_1, _read_result(DOC1_SP, DOC1_CONTENT)))
+        _body(MULTI_USER, (TOP_LEVEL_2, FOLDER_DEPLOYMENTS, _read_result(DOC1_SP, DOC1_CONTENT)))
     )
     assert flow == ("answer", DOC1_SP, DOC1_CONTENT)
 
@@ -320,9 +397,12 @@ def test_search_flow_found_step_without_tools_offered() -> None:
 
 
 def test_search_flow_ignores_catalog_and_read_results() -> None:
-    # A catalog (labeled lines) and a read result ("Document …" prefix)
+    # Listings (top-level + folder level, labeled file lines) and a read
-    # are NOT search results — the flow stays at the search step.
+    # result ("Document …" prefix) are NOT search results — the flow
-    flow = _search_flow(_body(SEARCH_USER, (CATALOG_2, _read_result(DOC1_SP, DOC1_CONTENT))))
+    # stays at the search step.
+    flow = _search_flow(
+        _body(SEARCH_USER, (TOP_LEVEL_2, FOLDER_DEPLOYMENTS, _read_result(DOC1_SP, DOC1_CONTENT)))
+    )
     assert flow == ("search",)
 
 

tests/unit/test_prompts.py

@@ -11,11 +11,15 @@ And the phase-71 deflection plain-text line (owner-permitted
 line; the ``DEFLECT_MODE`` marker-keying contract is unchanged and
 the line never leaks into the HIGH prompt.
 
-And the phase-72 ``<tools>`` copy: the document-identity contract is
+And the ``<tools>`` copy (phase 72: the document-identity contract
-stated up front (the ``ls`` source-name scope, the combined
+stated up front — the combined ``source/path`` identity for
-``source/path`` identity for ``read``/``grep``) — the same contract
+``read``/``grep``; phase 94, task 03: the ``ls`` clause rewritten to
-the teaching refusals in :mod:`app.rag.agent` re-state; the
+the drill-down tree contract — one level per call, sources at the
-``<tools>`` marker keying (HIGH only) is unchanged.
+top, folders + files below, ``grep`` as the without-listing locator —
+while the ``read``/``grep`` clauses and the discipline rules are
+byte-identical): the teaching refusals in :mod:`app.rag.agent`
+re-state the same contract; the ``<tools>`` marker keying (HIGH
+only) is unchanged.
 """
 from __future__ import annotations
 
@@ -194,20 +198,22 @@ pinned byte-for-byte in
 
 
 def test_tools_section_phase72_contract_clauses() -> None:
-    """Phase 72: the two contract clauses the teaching refusals
+    """Phase 72 + phase 94: the contract clauses the teaching refusals
     re-state after the fact, pinned byte-for-byte in the constant —
-    the ``ls`` source-name clause (its optional ``path`` is a source
+    the ``ls`` clause (phase 94: the drill-down tree contract — one
-    name, not a directory or file path; omit it to list every
+    level per call, sources at the top, folders + files below, never
-    document) and the ``read``/``grep`` combined-identity clause
+    the whole KB in one call, ``grep`` as the without-listing locator)
-    (the combined ``source/path`` string exactly as shown in the
+    and the ``read``/``grep`` combined-identity clause (the combined
-    ``ls`` output, *including the source name*; a bare document path
+    ``source/path`` string exactly as shown in the ``ls`` output,
-    will not resolve)."""
+    *including the source name*; a bare document path will not
-    # The ls source-name clause.
+    resolve)."""
-    assert (
+    # The ls drill-down clauses (phase 94, task 03).
-        "a source name (e.g. 'homelab'), not a directory or file "
+    assert "one level at a time" in TOOLS_SECTION
-        "path — omit it to list every document"
+    assert "lists every synced source with its document count" in TOOLS_SECTION
-    ) in TOOLS_SECTION
+    assert "that source's top-level folders and files" in TOOLS_SECTION
-    # The read combined-identity clause.
+    assert "never the whole knowledge base in one call" in TOOLS_SECTION
+    assert "to find one specific document without listing, use `grep`" in TOOLS_SECTION
+    # The read combined-identity clause (byte-identical across phases).
     assert (
         "combined `source/path` string, exactly as shown in the `ls` "
         "output — including the source name"
@@ -217,23 +223,25 @@ def test_tools_section_phase72_contract_clauses() -> None:
         "a bare document path (without the source name) will not resolve"
     ) == 2
     # The pre-phase-70 scope wording is gone — replaced by the
-    # explicit source-name contract.
+    # explicit source-name contract (and the phase-72 source-name-only
+    # clause by the phase-94 drill-down contract).
     assert "pass a source name as `path`" not in TOOLS_SECTION
+    assert "not a directory or file path" not in TOOLS_SECTION
 
 
 def test_tools_section_phase72_clauses_in_high_prompt_not_low() -> None:
-    """Phase 72: the contract clauses ride the HIGH prompt with the
+    """Phase 72/94: the contract clauses ride the HIGH prompt with the
     rest of the section and never leak into the LOW/deflection prompt
     (whose byte-identity is pinned in
     :func:`test_zero_note_prompt_is_byte_identical_to_pre_steering`)."""
     doc = _doc("kubernetes.md", "Talos Linux on three nodes.", "Kubernetes Homelab Cluster")
     high = build_high_prompt([doc])
     assert "<tools>" in high
-    assert "not a directory or file path" in high
+    assert "one level at a time" in high  # the phase-94 ls clause
     assert "including the source name" in high
     for low in (build_deflect_prompt(["T1"]), build_deflect_prompt([])):
         assert "<tools>" not in low
-        assert "not a directory or file path" not in low
+        assert "one level at a time" not in low
         assert "including the source name" not in low
 
 

tests/unit/test_sync_button.py

@@ -752,8 +752,9 @@ def _patch_sync_seams(
     """The runner's seams, monkeypatched on ``app.api.sync`` (the house
     mock-import pattern): fresh settings (no ``.env`` leak), a no-op
     model probe, a sentinel LLM client, one git row, the gated clone +
-    import, a no-op overview, and the DB-free sources-version step
+    import, a no-op overview, a no-op folder-summary step (phase 94 —
-    (dummy session + pinned counters)."""
+    the sentinel LLM client has no ``chat``), and the DB-free
+    sources-version step (dummy session + pinned counters)."""
     monkeypatch.setattr(
         sync_api,
         "get_settings",
@@ -783,6 +784,13 @@ def _patch_sync_seams(
 
     monkeypatch.setattr(sync_api, "regenerate_overview", fake_overview)
 
+    async def fake_folder_summaries(
+        db: object, llm: object, *, skip: bool = False
+    ) -> dict[str, int]:
+        return {"generated": 0, "failed": 0, "pruned": 0}
+
+    monkeypatch.setattr(sync_api, "generate_folder_summaries", fake_folder_summaries)
+
     class _DummySession:
         def close(self) -> None:
             pass