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`.

tests/integration/test_read_range_dedupe_two_ranges.py

@@ -411,7 +411,7 @@ def test_two_ranges_of_one_doc_both_reach_the_model(two_range_doc: Document) ->
     # the byte-identical line is now true).
     reread_result = llm.requests[3][0][7]
     assert reread_result["role"] == "tool"
-    assert reread_result["content"] == agent.ALREADY_IN_CONTEXT
+    assert reread_result["content"].startswith(agent.ALREADY_IN_CONTEXT)
 
     # Round 4: the answer echoes BOTH markers (the bug: pre-phase,
     # the echo could contain only marker A — range B's slice never
@@ -485,7 +485,10 @@ def test_truncated_plain_read_then_range_b_proceeds_and_plain_reread_teaches(
     assert isinstance(plain_result["content"], str)
     notice = READ_TRUNCATION_NOTICE.format(shown=cap, total=len(doc.content))
     assert plain_result["content"].startswith(f"Document {IDENTITY}:\n")
-    assert plain_result["content"].endswith(f"\n{TRUNCATION_MARKER}\n{notice}")
+    # Phase 160 (task 01): the budget-telemetry trailer rides the
+    # truncated result — the marker + notice end the RAW part.
+    raw = plain_result["content"].removesuffix(agent._budget_note(9))
+    assert raw.endswith(f"\n{TRUNCATION_MARKER}\n{notice}")
     assert MARKER_A in plain_result["content"]
     truncations = [p for p in pieces if isinstance(p, ToolResultPiece)]
     assert [(p.argument, p.chars_shown, p.chars_total) for p in truncations] == [
@@ -512,12 +515,12 @@ def test_truncated_plain_read_then_range_b_proceeds_and_plain_reread_teaches(
     # resolved doc.
     reread_result = llm.requests[3][0][7]
     assert reread_result["role"] == "tool"
-    assert reread_result["content"] == agent.REREAD_PARTIAL.format(
+    assert reread_result["content"].startswith(agent.REREAD_PARTIAL.format(
         covered=f"1–{covered}, {marker_b_line - 10}–{marker_b_line - 10 + RANGE_B_LIMIT - 1}",
         source=SOURCE,
         path=DOC_PATH,
         total=total_lines,
-    )
+        ))
 
     # Round 4: the answer echoes both markers.
     answer = _answer(pieces)