phase: 160_tool_budget_telemetry

All green. Final report:

**Phase 160 completion pass — verified (final verification; all 5 tasks already in `complete/`)**

- **Verified, no code defects found:** budget trailers (`TOOL_BUDGET_REMAINING/LAST/SPENT`), cap-path rejection + `ROUND_CAP_FALLBACK_ANSWER` + `ROUND_CAP_WRAPUP_INSTRUCTION`, `done.budget_exhausted` (ABSENT-when-false), `rounds=/cap_hit=` log fields, `agent_max_rounds=10` default, frontend Continue button + restore + shared-page exclusion, mock markers.
- **Tests/lint:** `uv run pytest` 153/153 green (EXIT 0); `uv run pytest --cov=app --cov-report=term-missing` TOTAL **99%** (>90%); `uv run ruff check .` clean; `uv run pyright` 0 errors/0 warnings.
- **Criteria:** ① decreasing trailer pinned by unit tests (9→…→spent) ✅ ② cap path ends readable, no tool lines after cap (E2E) ✅ ③ `budget_exhausted` true-only-on-cap, absent otherwise (integration) ✅ ④ Continue button → one fresh `continue` turn, fresh budget, record intact (E2E) ✅ ⑤ flag survives refresh; shared chat never renders it (`shared.js` has no `budget_exhausted` path) ✅ ⑥ `max_rounds=0` byte-identical single `tools=None` request; default still 10 ✅ ⑦ full suite/coverage/lint green ✅ ⑧ `test_tool_budget_telemetry.py` **7/7** in isolation; all 6 regression E2E suites green in isolation ✅ ⑨ commit + phase move = harness (I make no git history/index changes).
- **Docs:** README.md — fixed: the "Continue researching" button and cap behavior were undocumented (added a Chat-section paragraph + an Agent-tools-section paragraph, incl. the phase-71 recorded-revision note); env-var table, commands, and architecture all verified consistent otherwise. AGENTS.md — verified consistent, no changes needed.
- **Decisions:** no code changes required — phase was fully implemented; only README docs added. No live-infrastructure touched.
- **Next pending phase:** `161_reasoning_bubble`.

.agents/PLAN.md

@@ -139,8 +139,12 @@ POST /api/chat {message, history?}   (auth: require_user)
 SSE frames (`data: <json>\n\n`): `thinking` (before first delta) →
 `tool` (grounded turns, one per model call) → `retry` (pre-first-frame
 restarts) → `delta` (answer tokens) → `done` `{deflected, sources[],
-suggestions[]}` (terminal). Failure: `error` (terminal — no `done`, no
-`query_log` row; a pre-stream DB outage is a plain 503 JSON).
+suggestions[], budget_exhausted?}` (terminal). Failure: `error` (terminal — no `done`, no
+`query_log` row; a pre-stream DB outage is a plain 503 JSON). A
+`tools=None` request never emits a `tool` frame; a round-capped turn
+whose final reply carries no visible content answers with the budget
+fallback instead of erroring (phase 160, recorded revision of the
+phase-71 cap-path terminal, owner-confirmed 2026-10-05).
 `BOR_STREAM_THINKING=0` suppresses `thinking` frames server-side (chars
 still counted). LLM retries (A15 extension): retry count and delay are
 configurable (defaults: 3 retries, 5 s flat delay), **only before a
@@ -268,7 +272,8 @@ scripts.…`, and tests all honor it.
   ```
   question=… embed_ms=… top_score=… fts_hits=… summary_hits=… tuning=N
   kb_chars=N history_msgs=N threshold=… deflected=… sources=…
-  thinking_chars=… tool_calls=N total_ms=… retries=N scaffold_stripped=N
+  thinking_chars=… tool_calls=N rounds=N cap_hit=0|1 total_ms=…
+  retries=N scaffold_stripped=N
   ```
   (`sources=` = retrieval + agent-read docs, deduped; `tool_calls=`
   executed only; a cancelled turn writes neither line nor `query_log`