# Code Review Report — Job 120ffb08

## Summary

Cross-code review of commit `b490713` ("fix(loop): eliminate tmp script copy and trap leak in delegate_job_safe (P2-1/B-6)"). The commit eliminates temporary script copies in the skill tree, removes a trap that caused loop lock early release (D1) in command substitution subshells, adds diagnostic error logging for failed delegations, adds startup self-healing cleanup of stale .tmp files, and replaces 1 text-based test with 4 new behavioral tests.

**Verdict: PASS** — All changes are functionally correct. 58/58 tests pass across 5 test files. All syntax checks pass. Findings are Low/Info severity only.

---

## Scope

Files reviewed (commit `b490713`, 4 files, +211/-18):
1. `.agents/skills/multi-agent-mux-loop/scripts/run_loop.sh` — `delegate_job_safe` rewrite, diagnostic logging, startup cleanup
2. `tests/test_o3_scoped_guard.py` — 4 new behavioral tests replacing 1 old text-based test
3. `IMPROVEMENTS.md` — B-6 marked complete, B-12 (D1) documented
4. `LOG.md` — Change log entry

---

## Review Findings

### F1 (Low / Code Quality): `_extract_delegate_job_safe()` uses text parsing

**Location**: `test_o3_scoped_guard.py:148-156`

**Description**: The `_extract_delegate_job_safe()` helper extracts the function body from `run_loop.sh` via string search (`content.find("delegate_job_safe() {")` and `content.find("\n}\n", func_start)`). This is fragile if the function definition format changes (e.g., adding a space before `()`).

**Impact**: None currently — the format is stable and the assertion `assert func_start != -1` provides a clear failure message if parsing breaks.

**Recommendation**: No action required. Acceptable for a test helper.

### F2 (Info): `test_z9_probe_detects_the_defect` validates the test catches the bug

**Location**: `test_o3_scoped_guard.py:180-218`

**Description**: This test deliberately uses the OLD defective `delegate_job_safe` (with tmp copy + `trap _mam_release_guard EXIT`) inside a command substitution `$(delegate_job_safe submit --task test)`. It asserts `MARKER: RELEASED` — proving the trap fires in the subshell and releases the loop lock. This is excellent test design: it validates that the test suite would catch a regression if someone reintroduced the defect.

**Impact**: None — correct and valuable test.

**Recommendation**: No action required.

### F3 (Info): `test_z9_exit_code_and_diagnostics_propagation` omits `set -e`

**Location**: `test_o3_scoped_guard.py:255-281`

**Description**: This test deliberately omits `set -euo pipefail` to allow capturing the exit code via `delegate_job_safe submit --task test || rc=$?`. It verifies exit code propagation (`DELEGATE_RC: 7`), diagnostic logging (`delegate_job_safe failed (exit 7):`), and syntax check hint (`bash -n`).

**Impact**: None — correct test design for exit code testing.

**Recommendation**: No action required.

### F4 (Info): Startup self-healing cleanup

**Location**: `run_loop.sh:148`

**Description**: `rm -f "$REPO_ROOT/.agents/skills/multi-agent-mux-delegate-job/multi-agent-mux-delegate-job".*.tmp 2>/dev/null || true` cleans up stale .tmp files from previous runs that used the old code. The glob matches the old naming convention (`${orig_script}.${RANDOM}_$$.tmp`). The `2>/dev/null || true` ensures no error if no files match.

**Impact**: Correct — handles migration from old code gracefully.

**Recommendation**: No action required.

### F5 (Info): Diagnostic error logging placement

**Location**: `run_loop.sh:106-109`

**Description**: When `delegate_job_safe` fails (non-zero exit), it logs:
```
log_error "delegate_job_safe failed (exit $rc): $orig_script"
log_error "  if this loop edits framework skills in place, check that file's syntax:"
log_error "  bash -n \"$orig_script\""
```
The comment block (lines 90-101) explains why this is needed: callers' "Failed to register ..." branches are unreachable when the wrapper exits non-zero under `set -e` (the assignment aborts first), so diagnosis must be emitted inside `delegate_job_safe` itself.

**Impact**: Correct — provides actionable diagnostics for the most common failure mode (syntax errors in framework skills edited in-place during a loop).

**Recommendation**: No action required.

---

## Verification

### Syntax Checks
- `bash -n .agents/skills/multi-agent-mux-loop/scripts/run_loop.sh` — PASS
- `python3 -m py_compile tests/test_o3_scoped_guard.py` — PASS

### Test Suite
- `pytest tests/test_sanitize_and_mock_errors.py tests/test_sanity.py tests/test_o3_scoped_guard.py tests/test_herdr_shim_contract.py tests/test_b4_session_created.py -v`
- **Result: 58 passed in 22.54s**

### New Tests (test_o3_scoped_guard.py)
1. `test_z9_loop_lock_survives_delegation` — Verifies loop lock marker remains HELD after delegation with the new in-place code. PASS
2. `test_z9_probe_detects_the_defect` — Verifies the OLD defective code (tmp copy + trap) causes RELEASED, proving the test catches regressions. PASS
3. `test_z9_no_tmp_copy_left_in_skill_tree` — Verifies no .tmp files remain in the skill tree after delegation. PASS
4. `test_z9_exit_code_and_diagnostics_propagation` — Verifies exit code propagation (rc=7) and diagnostic logging (error message + bash -n hint). PASS

### Code Correctness Analysis

**delegate_job_safe rewrite**: The old code created a tmp copy (`cp "$orig_script" "$tmp_script"`), set a trap to clean it up, ran the copy, cleaned up, then re-set `trap _mam_release_guard`. The new code simply runs `bash "$orig_script" "$@"` in-place. This eliminates:
- B-6: Source tree pollution (no .tmp file created)
- D1: Loop lock early release (no `trap _mam_release_guard` in the subshell)

The `|| rc=$?` pattern correctly captures the exit code without `set -e` aborting the function, and the diagnostic logging provides actionable error messages for the most common failure mode.

**Startup cleanup**: The `rm -f .../*.tmp` line at startup provides self-healing for any stale .tmp files from previous runs that used the old code. The glob pattern and `2>/dev/null || true` are correct.

### Limitations
- shellcheck not available in environment (verified via `bash -n` instead)
- Full 256-test suite not re-run in this session (timed out); 58 directly-relevant tests pass
- IMPROVEMENTS.md and LOG.md changes are documentation-only, verified by reading

---

## Conclusion

The commit correctly eliminates the temporary script copy (B-6) and the trap leak (D1) by running the delegate-job wrapper in-place without any trap installation. The diagnostic error logging provides actionable feedback when the wrapper fails. The startup self-healing cleanup handles migration from old code. The 4 new behavioral tests are well-designed — they verify the fix works, prove the test catches the defect, confirm no .tmp files leak, and validate exit code/diagnostics propagation. No blocking issues found.

[VERDICT: PASS]