phase: 118_summary_seed_context

**Phase 118 final verification pass — complete.** All criteria verified; 4 pre-existing defects found and fixed.

- **Verified:** summary-seed wiring (`select_suggested` top-5 no-floor → summary blocks, no full text in HIGH prompt), all-doc markdown summaries + NULL backfill (`summary_backfilled`, no `sources_meta` bump), `read` adds full text with `read_docs`-only dedupe, `done.sources` = suggested+read / durable record = suggested+related+read + `suggested=N` log line (seen live in E2E), byte-locked PERSONA/LOW/TOOLS_SECTION, battery gate PASS recorded in `TOOL_CALLING_TESTING.md` §10 (turbo 2026-09-16: 1/2/4 GREEN, cond-3 reported 9/10 per A7, contract 21/21, caps 0).
- **Defects fixed (all pre-existing, none phase-118):** ① `ChatMessage` schema missing the phase-113 `related` key → `extra="forbid"` 422'd every done-time auto-save of grounded turns with a related tier, leaving `message_count=1` (root cause of `test_share_chat` 3F; browser-level instrumentation proved the PUT 422) — added the field + unit/integration pins; ② `test_theme_semantic_completion` pins stale vs phase-117 debox (border/chip removed) — re-targeted to assert border/chip *absence*; ③ `test_header_consistency` `<26`px pin red on 26.125px native date-input line — bound relaxed to `<34` (wrap-detection intent kept); ④ `test_navbar_refresh` bor.chat.v1 key set updated for `related`.
- **Test/lint/coverage:** `uv run pytest --cov=app --cov-report=term-missing` → **2506 passed, app/ 99%** (>90%); `uv run ruff check . && uv run pyright` → clean, 0 errors.
- **E2E:** new story suite in isolation → **2 passed**; full 103-suite matrix sweep (each isolated) → **all 103 green** after the fixes; `test_share_chat` 4 passed, `test_theme_semantic_completion` 8 passed, `test_header_consistency` 3 passed, `test_navbar_refresh` 7 passed.
- **Deviations:** none from LOCKED decisions. Note: orphaned diagnostic uvicorn processes briefly made E2E sessions exercise stale code — killed and re-verified; a sweep-regenerated tracked screenshot was restored. No commits made (harness commits).
- **Completion criteria:** all 7 ✅ (commit/phase-move is the harness's step).
- **Next pending phase:** none — `todo/` holds only this phase's overview pending the harness move.

tests/unit/test_config.py

@@ -282,6 +282,59 @@ def test_related_max_docs_rejects_negative(
         _settings()
 
 
+def test_suggested_docs_default_and_env_override(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Phase 118 (LOCKED A3): the start-here suggestion tier cap —
+    default 5 (the owner directive, TODO L3), env-tunable."""
+    monkeypatch.delenv("BOR_SUGGESTED_DOCS", raising=False)
+    assert _settings().suggested_docs == 5
+    monkeypatch.setenv("BOR_SUGGESTED_DOCS", "3")
+    assert _settings().suggested_docs == 3
+
+
+def test_suggested_docs_rejects_zero_and_negative(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """``0`` (no starting points) and a negative cap are typos (the
+    ``agent_max_rounds`` pattern); ``1`` is the minimum legal value."""
+    monkeypatch.setenv("BOR_SUGGESTED_DOCS", "0")
+    with pytest.raises(ValidationError, match="suggested_docs"):
+        _settings()
+    monkeypatch.setenv("BOR_SUGGESTED_DOCS", "-2")
+    with pytest.raises(ValidationError, match="suggested_docs"):
+        _settings()
+    monkeypatch.setenv("BOR_SUGGESTED_DOCS", "1")
+    assert _settings().suggested_docs == 1
+
+
+def test_suggestion_preview_chars_default_and_env_override(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Phase 118, task 03 (LOCKED A5): the NULL-summary preview cap —
+    default 400, env-tunable via ``BOR_SUGGESTION_PREVIEW_CHARS``."""
+    monkeypatch.delenv("BOR_SUGGESTION_PREVIEW_CHARS", raising=False)
+    assert _settings().suggestion_preview_chars == 400
+    monkeypatch.setenv("BOR_SUGGESTION_PREVIEW_CHARS", "800")
+    assert _settings().suggestion_preview_chars == 800
+
+
+def test_suggestion_preview_chars_rejects_zero_and_negative(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """``0``/negative would preview an empty/absent prefix — typos that
+    fail loudly (the ``agent_max_rounds`` pattern); ``1`` is the minimum
+    legal value."""
+    monkeypatch.setenv("BOR_SUGGESTION_PREVIEW_CHARS", "0")
+    with pytest.raises(ValidationError, match="suggestion_preview_chars"):
+        _settings()
+    monkeypatch.setenv("BOR_SUGGESTION_PREVIEW_CHARS", "-5")
+    with pytest.raises(ValidationError, match="suggestion_preview_chars"):
+        _settings()
+    monkeypatch.setenv("BOR_SUGGESTION_PREVIEW_CHARS", "1")
+    assert _settings().suggestion_preview_chars == 1
+
+
 def test_read_max_chars_default_and_env_override(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None: