phase: 161_reasoning_bubble

All gates verified. Final check — AGENTS.md rules against the project (commands, gates, protocols) — the quick-reference commands all exist and the rules (PLAN §2/§7/§9 references, phase protocol, No CDN, Debugpy, git gates) accurately describe the project; the reasoning bubble is a pure UI change with no new commands or env vars, so no AGENTS.md change is needed.

**Verification complete — full results:**

- **Verified** (implemented by prior task passes, all in working tree): `createReasoningWrap`/`ensureReasoningWrap` live container (D1), `settleReasoning` fold at the 3 settle sites + not at delta (D2), 320px `.reasoning-body` window + pinned-tail follow (D3), zero persistence change (D4), collapsed restore + shared-page parity with D6 step counts, `styles.css` family treatment + reduced-motion still, mock `REASONING_MIDROUND_TRIGGER` flow, 6-test story suite, phase-158 pin updates
- **Full suite:** `uv run pytest` → **3738 passed, 0 failed** · `uv run pytest --cov=app --cov-report=term-missing` → **TOTAL 99% (>90%)** · `uv run ruff check .` → all checks passed · `uv run pyright` → **0 errors, 0 warnings**
- **E2E in isolation** (DB up; port-8123 collision with an unrelated `undercooked` service → `E2E_APP_PORT=8125`/`E2E_MOCK_PORT=8902`, no live change made): `test_reasoning_bubble.py` **6/6** · `test_thinking_timeline.py` ✓ · `test_thinking_display.py` ✓ · `test_tool_call_compact.py` ✓ · `test_big_read_progress.py` ✓ · `test_turn_progress_loader.py` ✓ · `test_share_chat.py` ✓ · `test_chat_persistence.py` ✓ · `test_smoke.py` ✓ (all exit 0, zero failures)
- **Completion criteria:** all 9 checked against the code + test outcomes — container open/live/nested ✓, stays open past mid-round delta ✓, folds at done ✓, restore + shared collapsed with "3 steps" ✓, plain turn = no container ✓, regression suites green ✓, suite/coverage/lint green ✓, diff scope limited to `frontend/assets/{app.js,shared.js,styles.css}` + `tests/` + `README.md` + phase files (no `app/` — D4) ✓
- **Documentation:** README.md "Thinking" section names the Reasoning bubble accurately (320px window, open-until-settle incl. mid-round deltas, "N steps", byte-identical no-container, collapsed on restore/shared) — verified consistent, no changes needed; AGENTS.md — verified consistent, no changes needed; all `.env.example` vars documented
- **Decisions:** commit + phase-dir move left to the harness (per pass rules — no git index/history commands executed); `undercooked` dev server on port 8123 untouched, E2E used the env port overrides
- **Next pending phase:** none — `161_reasoning_bubble` is the last in `todo/`

tests/unit/test_tool_call_compact.py

@@ -63,14 +63,17 @@ def _fn(src: str, name: str) -> str:
 
 
 def test_tool_run_builds_an_open_details_disclosure() -> None:
-    """Phase 158 (D1/D2/D5): ``ensureToolRun`` creates a native
-    ``details.tool-calls-disclosure`` via ``createToolDisclosure`` —
-    a ``summary.tool-calls-summary`` (first child) + the existing
-    ``.tool-calls`` list (role=list + aria-label "Tool calls",
-    second child) — inserted before the bubble in arrival order (D2).
-    It starts OPEN while the run is live; every append re-renders the
-    plain-text per-run "Tool call(s) (N)" count on the summary
-    through textContent (no innerHTML anywhere)."""
+    """Phase 158 (D1/D5) + 161 (D1): ``ensureToolRun`` creates a
+    native ``details.tool-calls-disclosure`` via
+    ``createToolDisclosure`` — a ``summary.tool-calls-summary``
+    (first child) + the existing ``.tool-calls`` list (role=list +
+    aria-label "Tool calls", second child) — appended into the
+    phase-161 reasoning container's ``.reasoning-body`` in arrival
+    order (D1 — the container sits above the bubble; the per-run
+    bubble anchor is superseded). It starts OPEN while the run is
+    live; every append re-renders the plain-text per-run "Tool
+    call(s) (N)" count on the summary through textContent (no
+    innerHTML anywhere)."""
     js = _js()
     disc = _fn(js, "createToolDisclosure")
     assert "document.createElement(\"details\")" in disc
@@ -92,8 +95,15 @@ def test_tool_run_builds_an_open_details_disclosure() -> None:
         "calls and the phase-87 .tool-elapsed suffix stay visible during "
         "the turn"
     )
-    assert 'insertBefore(disc, body.querySelector(".bubble"))' in run, (
-        "D2: above the answer, in arrival order"
+    assert 'insertBefore(disc, body.querySelector(".bubble"))' not in run, (
+        "the per-run bubble anchor is GONE (phase 161 D1)"
+    )
+    assert (
+        'ensureReasoningWrap(wrap).querySelector(".reasoning-body")'
+        ".appendChild(disc)" in run
+    ), (
+        "phase 161 (D1): appended into the container's body — the "
+        "container sits above the answer, arrival order preserved"
     )
     # D5: the count rides the summary — the template fragment itself
     # (singular for one call, plural otherwise), textContent-built.
@@ -169,19 +179,28 @@ def test_restore_path_folds_the_disclosure() -> None:
     ), "the fold sits AFTER the tool-line restore loop"
 
 
-def test_run_anchors_are_the_bubble_in_arrival_order() -> None:
-    """Phase 158 (D2): the anchor is the BUBBLE for both run kinds —
-    the old ``.tool-calls-disclosure ?? .tool-calls ?? .bubble``
-    anchor chain is GONE (with per-run disclosures, "above the
-    tool lines" was the wrong order — arrival order is the
-    contract), and the runs still open while active (D5)."""
+def test_run_anchors_are_the_container_in_arrival_order() -> None:
+    """Phase 158 (D2) + 161 (D1): the anchor moved to the REASONING
+    CONTAINER for both run kinds (the phase-161 documented
+    supersession — the container sits before the bubble; the runs
+    append into its ``.reasoning-body``) — the old
+    ``.tool-calls-disclosure ?? .tool-calls ?? .bubble`` anchor chain
+    is GONE (with per-run disclosures, "above the tool lines" was the
+    wrong order — arrival order is the contract), and the runs still
+    open while active (D5)."""
     js = _js()
     run = _fn(js, "ensureThinkingRun")
-    assert 'querySelector(".bubble")' in run
+    assert (
+        'ensureReasoningWrap(wrap).querySelector(".reasoning-body")'
+        ".appendChild(block)" in run
+    ), "phase 161 (D1): the thinking run anchors on the container"
     assert "block.open = true" in run
     assert "??" not in run, "the old anchor chain is GONE"
     d = _fn(js, "ensureToolRun")
-    assert 'querySelector(".bubble")' in d
+    assert (
+        'ensureReasoningWrap(wrap).querySelector(".reasoning-body")'
+        ".appendChild(disc)" in d
+    ), "phase 161 (D1): the tool run anchors on the container"
     assert "disc.open = true" in d