Codex Panel A/B (contributor instrument, verdict decided)

Answer one question with evidence: do dimension-focused codex passes find real issues that one holistic codex exec review misses? Runs both on the same diff, then classifies every focused finding against the holistic pass.

DECIDED 2026-07-10 after 4 runs (2 fresh): panel KILLED. Fresh-only 1 real miss / 1 false positive plus one zero-value run at 4× cost, > real misses did not outnumber FPs. Kept as contributor tooling (NOT distributed) for one possible retest: a UI-heavy diff with a single extra liveview-focused pass (2× cost). Scoreboard: .claude/research/2026-07-03-codex-review-integration.md §7.

Usage

/codex-ab            # A/B against main (~5 min, 4 codex runs)
/codex-ab develop    # explicit base branch

Iron Laws

1. FRESH DIFF ONLY, ask the user to confirm this branch has NOT been codex-reviewed yet (cloud or /phx:codex-loop). A drained diff returns NO FINDINGS everywhere and proves nothing, wasted quota
2. Verify every REAL MISS in the code before counting it, a focused finding only scores if the issue actually exists at that file:line
3. Read ONLY the findings .md files, streams are diverted to .log files; never cat a log into context (10k+ lines each)
4. Exactly 4 codex runs, never re-run dimensions, bounded quota
5. Persist the verdict, an unrecorded experiment is wasted quota

Workflow

Step 1: Preflight

Run command -v codex, missing → STOP with install hint. Then:

• git status --short dirty → warn (codex flags local dirt as findings)
• Ask: "Has codex already reviewed this branch (PR review or codex-loop)?" If yes → STOP, explain the fresh-diff requirement (Iron Law 1)

Step 2: Run the A/B (background, ~5 min)

bash ${CLAUDE_SKILL_DIR}/scripts/codex-panel-ab.sh {base} \
  .claude/reviews/codex-ab-$(date +%Y-%m-%d-%H%M)