codex-review

name	codex-review
description	Ask Codex to review Shannon work. Use when the user requests Codex review or during large/risky experiments before acting on conclusions.

Codex Review

Use Codex as an independent reviewer for Shannon issue designs, code diffs, experiment results, and architectural decisions.

The review is advisory. The calling agent remains responsible for deciding whether Codex's feedback is correct, acting on valid findings, and explaining any rejected findings.

Do not rely on Codex session memory alone. Session IDs are useful for grouping related reviews and may help continuity, but every important review prompt must include the essential issue, diff, log, and question context explicitly.

This skill is the Codex counterpart of claude-review. Use either or both when you want a second model's read on risky work.

When This Skill Applies

Use this skill when:

• the user asks for "codex review", "ask Codex", or similar;
• an experiment is large, risky, or touches the Nushell/Reedline fork surface;
• an experiment has already failed once and the next design needs review;
• a code change affects architecture, shell state synchronization, process handling, signal handling, config loading, terminal behavior, or persistent state;
• before closing an issue after a complex series of experiments.

Review Timeout

Every Codex review has a hard timeout of 15 minutes.

Use the helper script in this skill instead of calling codex directly. The script enforces the timeout with Python's subprocess API and terminates Codex's process group on timeout because macOS does not provide a portable timeout command by default.

Files and Logs

All review state and output lives under:

logs/codex-review/

The helper script maintains:

Path	Purpose
logs/codex-review/current-session-id	reusable Codex session UUID
logs/codex-review/<timestamp>-prompt.md	exact prompt sent to Codex
logs/codex-review/<timestamp>-events.jsonl	raw Codex --json event stream
logs/codex-review/<timestamp>-last-message.md	Codex's final review message
logs/codex-review/<timestamp>-stderr.log	Codex stderr / timeout details

These logs are intentionally under logs/, which is gitignored. They may still contain sensitive diffs or local paths. Keep context narrow and do not write secrets into review prompts.

Process

1. Prepare the review context. Include only the context Codex needs. Prefer concrete artifacts:

   • the user's current request;
   • the issue file and experiment section;
   • relevant git diff or git diff --staged;
   • test commands and observed outputs;
   • screenshots/log paths when those are part of the evidence.

2. Ask specific questions. The prompt should tell Codex what kind of review to perform. Examples:

   • "Audit this experiment design for contradictions, missing verification, and architectural risks."
   • "Review this diff for correctness, regressions, and missing tests."
   • "Given these logs, identify what failed and what experiment should come next."

3. Run the helper script.

   python3 skills/codex-review/scripts/codex_review.py \
     --context issues/0789-electron-style-pdf-viewer/README.md \
     "Audit Experiment 6. Focus on whether the scope is right and whether the verification would prove the result."
   

   For a staged diff review:

   git diff --staged | python3 skills/codex-review/scripts/codex_review.py \
     "Review this staged diff for bugs, regressions, and missing tests."
   

   For a fresh thread:

   python3 skills/codex-review/scripts/codex_review.py --new-session \
     "Start a new review thread. Reply with the review session status."
   

4. Read the result. The helper prints:

   • the session ID;
   • the prompt path;
   • the raw event-stream path;
   • the final-message path;
   • the extracted Codex text when a final message was captured.

5. Act on valid findings. If Codex finds a real issue and the user asked for implementation, fix it. If Codex is wrong or speculative, do not make the change; briefly document why.

6. Report high-signal results. Summarize Codex's actionable findings to the user. Do not paste long raw output unless the user asks for it.

Session Handling

Codex differs from Claude here. claude -p lets you choose a session id up front with --session-id <uuid>. Codex does not: codex exec generates the id itself. The helper therefore captures the id from the --json event stream after the first run and stores it for follow-ups.

The helper uses codex exec for a new review thread and codex exec resume <uuid> for follow-up turns.

Default policy: maintain one continuous review session while it is usable. The helper resumes the stored session id on every run. Keep doing that — review after review goes into the same thread until the session becomes unusable.

• Do NOT pass --new-session on your own judgment for ordinary topic changes. Not for a "different topic," not for a new experiment, not for a new issue. The user decides when to start a new thread, except for the automatic recovery cases below.
• If logs/codex-review/current-session-id exists and holds a valid UUID, the script resumes it. If it is missing or unparseable, the script starts a fresh session and stores the id Codex reports.
• Automatic self-heal. If resuming the stored session fails because the id stopped working (expired/unknown), or because the stored session is too full and Codex reports a context-window/compaction failure, the helper retries once as a fresh session, adopts the new id, and prints a note. You do not need to fall back to another reviewer — just use the fresh Codex session result.
• If you call the helper and manually observe a full-session error such as context_length_exceeded, context window, or a failed remote compaction, rerun the same Codex review with --new-session. Do not switch to Claude or another agent merely because the old Codex session is full.
• --new-session (explicit user request only) ignores the stored id and starts fresh.
• Always include the essential context again on every review. Resuming the same session id works, but model-visible history should not be treated as guaranteed.
• codex exec resume --last is a manual fallback if you ever need to reattach to the most recent session by hand.

Codex Command Shape

The helper invokes Codex like this for a new session:

codex exec \
  -s read-only \
  --json \
  --color never \
  -o logs/codex-review/<timestamp>-last-message.md \
  -   # prompt is piped in on stdin

For follow-up turns it replaces codex exec with codex exec resume <uuid> and drops -s (see below).

The default sandbox is read-only, which is genuinely read-only — Codex can read the repo to inspect files but cannot modify the working tree. codex exec is non-interactive by design, so it never blocks on an approval prompt (there is no -a flag on codex exec). This is the review-oriented analog of claude-review's read-only Read/Grep/Glob tool set under --permission-mode dontAsk.

The sandbox is fixed when the session is created. codex exec resume does not accept -s; a resumed turn inherits the sandbox the session was created with. To review under a different sandbox, start a new session with --new-session.

If a review truly needs to run commands (not just read), create the session with a workspace-write sandbox and include the reason in the user-facing summary:

python3 skills/codex-review/scripts/codex_review.py --allow-bash ...

If a review should use only supplied context, run with:

python3 skills/codex-review/scripts/codex_review.py --no-tools ...

--no-tools is best-effort: Codex has no per-tool allowlist for codex exec, so the helper keeps the read-only sandbox and instructs Codex in the prompt to use only the supplied context.

Prompt Template

Use this structure for substantial reviews:

You are reviewing Shannon work. Take a code-review stance: findings first,
ordered by severity, with file/line references where possible.

Task:
<what Codex should review>

Context:
<issue, experiment, diff, logs, screenshots, test output>

Questions:
1. Is the design/implementation correct?
2. What are the concrete risks or missed cases?
3. What should be changed before implementation/commit?
4. If nothing should change, say that clearly.

Automatic Use in Large Experiments

For large experiments, run Codex review at one or both checkpoints:

1. After designing the experiment, before implementation. Ask Codex to audit the design for contradictions, missing verification, and scope creep.

2. After implementation, before final result or commit. Ask Codex to review the diff, logs, and result language.

Do not block forever waiting for Codex. The 15-minute timeout is the maximum. If Codex times out, record that and continue with normal engineering judgment.

Smoke Test

After creating or changing this skill, test the helper without giving Codex repo-changing authority:

python3 skills/codex-review/scripts/codex_review.py --new-session --no-tools \
  "Smoke test: reply with OK and one sentence describing what session continuity means."

Then run a second call without --new-session:

python3 skills/codex-review/scripts/codex_review.py --no-tools \
  "In one sentence, say whether this is the same review session."

Both outputs should be saved under logs/codex-review/. The printed session_id should match between the two runs. The second answer does not need to prove memory of the first prompt; the important smoke-test properties are exit code 0, saved artifacts, and stable session ID reuse.