multi-agent-mux/.agents/reports/canary-projects-multi-agent-mux-creator-cline/report-86163ca6.md

Cross-Code Review Report: B-13 Stage 2 — Runtime Freeze Snapshot

• Job ID: 86163ca6
• Reviewer: cline
• Date: 2026-08-17
• Scope: B-13 Stage 2 runtime freeze snapshot in run_loop.sh, 5 new regression tests in tests/test_o3_scoped_guard.py, and documentation updates in IMPROVEMENTS.md and VERSIONS.md

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1. Changeset Overview

File	Lines Changed	Description
.agents/skills/multi-agent-mux-loop/scripts/run_loop.sh	+44/-27	Freeze snapshot logic, argv capture, MAM_REAL_ROOT separation, extended _mam_release_guard
tests/test_o3_scoped_guard.py	+102/-0	5 new B-13 regression tests
IMPROVEMENTS.md	+16/-7	B-13 moved from open to completed; 271/271 test count
VERSIONS.md	+9/-0	New entry #8 for B-13/Stage 2
Total	+174/-31	4 files

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2. Lint Perspective

2.1 Bash Syntax (run_loop.sh)

• bash -n run_loop.sh → PASS (no syntax errors)
• shellcheck not available on this system; manual review performed

2.2 Bash 3.2 Compatibility

• ${MAM_LOOP_ARGV[@]+"${MAM_LOOP_ARGV[@]}"} (line 108): Valid bash 3.2 guard for expanding potentially empty arrays. Without this guard, bash 3.2 (macOS default) would error on "${MAM_LOOP_ARGV[@]}" when the array is empty. Correct.

2.3 Python Compilation (test_o3_scoped_guard.py)

• py_compile test_o3_scoped_guard.py → PASS (no compile errors)
• All imports (os, json, shutil, subprocess, time, Path, pytest) are used; no unused imports introduced

2.4 Code Style

• Variable naming (MAM_LOOP_ARGV, MAM_REAL_ROOT, MAM_LOOP_FREEZE_DIR, MAM_LOOP_FREEZE_OWNED, MAM_LOOP_NO_FREEZE) follows existing MAM_* convention
• Comment style matches existing patterns (Korean/English mixed, inline references to bug IDs)
• No trailing whitespace or formatting issues introduced

Lint Verdict: PASS

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3. Operability Perspective

3.1 Full Test Suite

• 271 passed in 445.76s (0:07:25) — EXIT_CODE:0
• Previous baseline: 266 tests (job 2f64681f). New total: 266 + 5 B-13 tests = 271. Consistent.
• Test count in IMPROVEMENTS.md (271/271) and VERSIONS.md (271/271) matches actual results.

3.2 B-13 Regression Tests (5/5 PASS in 0.34s)

Test	Status	What It Verifies
test_b13_reexec_preserves_original_argv	PASS	Argv forwarded through freeze re-exec (arg parser consumes $@ via shift)
test_b13_freeze_survives_broken_wrapper	PASS	Frozen copy immune to wrapper broken mid-loop
test_b13_freeze_dir_is_outside_the_skill_tree	PASS	No files written under .agents/skills/ (B-6 boundary)
test_b13_release_guard_cleans_up_and_releases_lock	PASS	Extended _mam_release_guard releases lock + removes snapshot
test_b13_no_freeze_switch_disables_reexec	PASS	MAM_LOOP_NO_FREEZE=1 skips freeze entirely

3.3 Existing Test Regression Check

• All 27 pre-existing tests in test_o3_scoped_guard.py still pass (32/32 total in file)
• No regressions detected in any test file

3.4 Live Freeze Verification

• During this review, the actual run_loop.sh orchestrator (PID 88241) was observed running from /var/folders/.../mam-loop-freeze.L2nD67/.agents/skills/multi-agent-mux-loop/scripts/run_loop.sh — confirming the freeze mechanism works in production, not just in tests.

3.5 Freeze Logic Analysis

Code path vs. Data path separation:

Variable	After Re-exec	Used For	Correct?
$REPO_ROOT	Freeze dir (e.g., /tmp/mam-loop-freeze.XXXXXX)	Loading scripts (source), running wrapper (delegate_job_safe)	Yes — code runs from frozen snapshot
$MAM_REAL_ROOT	Original repo (e.g., /Users/.../multi-agent-mux)	Lock marker, .tmp cleanup, git rev-parse, mam_collect_changes_diff	Yes — state/git ops use real repo

3 $REPO_ROOT → $MAM_REAL_ROOT conversions (lines 175, 488, 580):

• Line 175: rm -f "$MAM_REAL_ROOT/.agents/skills/..." — cleans .tmp files in real repo (was $REPO_ROOT)
• Line 488: BASE_COMMIT=$(cd -P "$MAM_REAL_ROOT" ...) — git operations in real repo (was $REPO_ROOT)
• Line 580: mam_collect_changes_diff "$MAM_REAL_ROOT" ... — diff collection in real repo (was $REPO_ROOT)

All remaining $REPO_ROOT usages (lines 17, 19, 21, 101, 104-106, 130) are correct — they either load scripts from the freeze dir or export env vars before the re-exec.

Graceful degradation:

• If mktemp -d fails or cp -R fails, the freeze is aborted, the temp dir is cleaned up, and a warning is printed via echo (not log_warn, which isn't defined until line 141). The script continues unfrozen. Correct.

Cleanup safety:

• _mam_release_guard only deletes the freeze dir if MAM_LOOP_FREEZE_OWNED=1 (set by the freeze creator)
• case "$MAM_LOOP_FREEZE_DIR" in */mam-loop-freeze.*) rm -rf ... — pattern guard prevents accidental deletion of arbitrary directories. Safe.

Operability Verdict: PASS

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4. Loss Perspective

4.1 Behaviors Preserved

• Lock acquisition/release mechanism unchanged (mam_acquire_loop_lock / mam_release_loop_lock)
• delegate_job_safe still runs wrapper from $REPO_ROOT (which is now the freeze dir — correct)
• --all-reviewer, --max-loop, --verbose etc. all work the same (argv preserved through re-exec)
• .mam.env loading preserved via MAM_ENV_FILE export (wrapper checks MAM_ENV_FILE first)

4.2 Behaviors Changed (Intentional)

• run_loop.sh now re-execs from a frozen snapshot at startup (by default)
• _mam_release_guard extended with freeze dir cleanup (additive — lock release still works)
• 3 git/state operations switched from $REPO_ROOT to $MAM_REAL_ROOT (necessary after freeze)
• MAM_LOOP_NO_FREEZE=1 opt-out switch added (for testing/debugging)

4.3 No Unintended Losses

• No functions removed or renamed (only orig_script → wrapper_script cosmetic rename in delegate_job_safe)
• No environment variables removed
• No existing test modified or removed
• Old comment about "deliberately creates no copy" replaced with accurate description of freeze mechanism

Loss Verdict: PASS

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5. Documentation Review

5.1 IMPROVEMENTS.md

• B-13 moved from "Section 2: Edge-case Bugs" (open) to "Section 5: Completed Tasks" (completed)
• Open task count: 3 → 2 (correct)
• Completed task count: 22 → 23 (correct, B-13 added)
• B-13 completion entry includes: freeze mechanism, B-13 layer (bash byte-offset), B-6 distinction, P1/C1/C2 corrections, cleanup logic, 5 regression guards
• Priority table updated with B-13 entry
• Test count updated to 271/271

5.2 VERSIONS.md

• New entry #8 added under current version section
• Covers: freeze mechanism, code/state root separation, argv preservation, echo fallback, MAM_LOOP_NO_FREEZE=1, 5 regression guards, 271/271 PASS
• Accurate and comprehensive

5.3 Test Name Consistency

• All 5 test names in IMPROVEMENTS.md match actual code exactly. No discrepancies.

Documentation Verdict: PASS

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6. Edge Cases & Safety Analysis

Scenario	Handling	Risk
SIGKILL during loop	Trap doesn't fire; freeze dir leaks in $TMPDIR	Low — OS cleans $TMPDIR on reboot; no source tree pollution
Concurrent loops	Each gets unique mktemp -d name; loop lock prevents concurrent execution	None
Freeze copy race	Freeze happens at init before any workers start	None
cp -R with symlinks	Symlinks preserved as-is in freeze	Low — .agents/skills/ has no external symlinks
Empty argv ($#=0)	${MAM_LOOP_ARGV[@]+...} guard handles empty array in bash 3.2	None
mktemp failure	_freeze="", falls through to warning + unfrozen continuation	None — graceful degradation
.mam.env absent	[ -f "$REPO_ROOT/.mam.env" ] && export ... — short-circuits if absent	None

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7. Summary

The B-13 Stage 2 implementation correctly addresses the self-hosting loop runtime freeze problem. The freeze snapshot mechanism is sound: it captures .agents/skills/ into a temp directory at loop initialization and re-execs from the frozen copy, making the running loop immune to mid-loop skill edits. The code path / data path separation ($REPO_ROOT for code, $MAM_REAL_ROOT for state) is clean and correct. All 271 tests pass, including 5 new B-13 regression tests. No regressions, no losses, no lint issues.

[VERDICT: PASS]