/codex-loop

name: codex-loop
description: Fix Elixir/Phoenix code until Codex CLI review comes back clean — bounded review, fix, verify loop before opening a PR. Use when codex is installed and you want an external cross-model critic on your changes before pushing.
effort: medium
argument-hint: "[--base <branch>] [--uncommitted] [--auto] [--max-rounds N]"

Codex Loop (fix until clean)

Critic→Refiner loop with the Codex CLI as external critic: review → fix approved findings → verify → re-review, until codex is clean or rounds run out. Codex reviews; Claude fixes. Complements `/phx:review` (Claude panel) — run either or both before a PR.

Usage

/phx:codex-loop                    # diff vs default branch, interactive
/phx:codex-loop --uncommitted      # staged + unstaged + untracked
/phx:codex-loop --base develop     # explicit base branch
/phx:codex-loop --auto             # auto-approve P0/P1/P2, skip P3
/phx:codex-loop --max-rounds 2     # default 3

Iron Laws

1. **BOUNDED rounds — never exceed --max-rounds (default 3)** — each round costs codex quota; report remaining findings instead of looping on 2. **Verify BEFORE re-review** — `mix compile --warnings-as-errors` + tests must pass before burning a codex round on broken code 3. **NEVER commit or push** — leave git to the user 4. **Codex findings get Iron Law scrutiny** — decline suggestions that violate an Iron Law, with explanation in the round report 5. **Skipped findings are reported, never dropped** — every finding ends as fixed, declined (with reason), or deferred-by-user 6. **Missing CLI stops the skill with an install hint** — suggest `/phx:review` as the codex-free alternative; never crash

Workflow

Step 1: Preflight

Run `command -v codex`. If missing: STOP. Show the install hint (`brew install codex` or `npm i -g @openai/codex`, then `codex login`; `codex doctor` to diagnose) and suggest `/phx:review`.

Then two cheap checks that save review rounds:

• **Dirty tree** (`git status --short`, only when using `--base`): codex

inspects working-tree state too and WILL flag local dirt (stray edits, dirty submodules) as findings. Surface the dirt and ask: clean/stash first, or proceed knowing round 1 may spend findings on it.

• **Missing rubric**: if `AGENTS.md` has no `## Review guidelines`

section, note once that `/phx:init` installs the Elixir rubric that steers codex priorities — then proceed (it works without, on defaults).

Step 2: Detect Diff Mode

• **Flag passed** (`--base`/`--uncommitted`) → use as given
• **Commits ahead of the default branch** → `--base {default}`
• **No commits yet** → `--uncommitted`

Step 3: Review Round (max `--max-rounds`, default 3)

1. **Review** — ONE foreground Bash call, explicit `timeout: 600000` (large diffs run 10+ min). On timeout with the process alive: ONE `until [ -f {out} ]; do sleep 5; done` wait — never poll-spam or `pkill` a running review (quota is spent either way). ALWAYS silence the streams — only the `-o` file matters (10k+ lines otherwise):

   codex exec review --base {branch} --ephemeral \
     -o /tmp/codex-round-{n}.md > /tmp/codex-round-{n}.log 2>&1

NEVER pass custom instructions with a diff-mode flag — the CLI rejects the combination; the rubric comes from AGENTS.md `## Review guidelines` (`/phx:init`). Parse the output file, NOT the exit code (0 even with findings). Recipes: `${CLAUDE_SKILL_DIR}/references/codex-cli.md`.

**Retired model** (exit 1, no `-o` file, log: `model is not supported` / `Model not found`): resolve the account default — `MODEL=$(codex debug models | jq -r '.models | map(select(.visibility == "list")) | sort_by(.priority) | .[0].slug')` — retry once with `-m "$MODEL" -c review_model="$MODEL"` (both: a pinned `review_model` beats `-m`), reuse it every round, never hardcode a slug. Tell the user once to set `model`/`review_model = "$MODEL"` in `~/.codex/config.toml`.

2. **Clean check** — parse the output file; no `- [P{n}]` bullets means CLEAN → go to Step 5.

Step 4: Triage, Fix, Verify

1. **Triage** — emit the findings table (`# | P | file:line | title | proposed action`) as **visible response text BEFORE any `AskUserQuestion` call** — a table composed only in thinking never renders. Then ask approve-or-skip per finding (`AskUserQuestion`). With `--auto`: approve P0/P1/P2, skip P3 (list skipped in the round report).

2. **Fix** — apply approved fixes with user-visible diffs. Check each against Iron Laws first (Law 4).

3. **Verify** — scoped, before the next round:

   mix format {changed_files} && \
   mix compile --warnings-as-errors && mix test {affected_tests}

If verification fails 3 times, STOP with a BLOCKER report — do not burn another codex round on broken code.

4. Next round (n+1) — back to Step 3.

Step 5: Final Report

## Codex Loop Report — {CLEAN | MAX ROUNDS REACHED | BLOCKED}
Rounds: {n}/{max} | Fixed: {n} | Declined (Iron Law): {n} | Deferred: {n}
{per-round: findings → outcome}
{remaining findings if not CLEAN}

On CLEAN: suggest `/phx:compound` for non-obvious fixes, then commit/PR. On MAX ROUNDS: list remaining findings; offer `/phx:plan` to convert them into a follow-up plan.

Integration

implement → /phx:codex-loop (YOU ARE HERE) → clean → commit/PR → /phx:watch-pr --codex
     ↑ or arrive from /phx:review --codex verdict REQUIRES CHANGES

References

• `${CLAUDE_SKILL_DIR}/references/codex-cli.md` — invocation recipes, parse

patterns, verified gotchas (CLI 0.142.5; model fallback 0.162.1)