17 KiB
| name | description |
|---|---|
| codex | OpenAI Codex CLI wrapper — three modes. Code review: independent diff review via codex review with pass/fail gate. Challenge: adversarial mode that tries to break your code. Consult: ask codex anyth |
/codex — Multi-AI Second Opinion
You are running the /codex skill. This wraps the OpenAI Codex CLI to get an independent,
brutally honest second opinion from a different AI system.
Codex is the "200 IQ autistic developer" — direct, terse, technically precise, challenges assumptions, catches things you might miss. Present its output faithfully, not summarized.
Step 0: Check codex binary
CODEX_BIN=$(which codex 2>/dev/null || echo "")
[ -z "$CODEX_BIN" ] && echo "NOT_FOUND" || echo "FOUND: $CODEX_BIN"
If NOT_FOUND: stop and tell the user:
"Codex CLI not found. Install it: npm install -g @openai/codex or see https://github.com/openai/codex"
Step 1: Detect mode
Parse the user's input to determine which mode to run:
/codex reviewor/codex review <instructions>— Review mode (Step 2A)/codex challengeor/codex challenge <focus>— Challenge mode (Step 2B)/codexwith no arguments — Auto-detect:- Check for a diff (with fallback if origin isn't available):
git diff origin/<base> --stat 2>/dev/null | tail -1 || git diff <base> --stat 2>/dev/null | tail -1 - If a diff exists, use question:
Codex detected changes against the base branch. What should it do? A) Review the diff (code review with pass/fail gate) B) Challenge the diff (adversarial — try to break it) C) Something else — I'll provide a prompt - If no diff, check for plan files scoped to the current project:
ls -t ~/.claude/plans/*.md 2>/dev/null | xargs grep -l "$(basename $(pwd))" 2>/dev/null | head -1If no project-scoped match, fall back to:ls -t ~/.claude/plans/*.md 2>/dev/null | head -1but warn the user: "Note: this plan may be from a different project." - If a plan file exists, offer to review it
- Otherwise, ask: "What would you like to ask Codex?"
- Check for a diff (with fallback if origin isn't available):
/codex <anything else>— Consult mode (Step 2C), where the remaining text is the prompt
Step 2A: Review Mode
Run Codex code review against the current branch diff.
- Create temp files for output capture:
TMPERR=$(mktemp /tmp/codex-err-XXXXXX.txt)
- Run the review (5-minute timeout):
codex review --base <base> -c 'model_reasoning_effort="xhigh"' --enable web_search_cached 2>"$TMPERR"
Use timeout: 300000 on the Bash call. If the user provided custom instructions
(e.g., /codex review focus on security), pass them as the prompt argument:
codex review "focus on security" --base <base> -c 'model_reasoning_effort="xhigh"' --enable web_search_cached 2>"$TMPERR"
- Capture the output. Then parse cost from stderr:
grep "tokens used" "$TMPERR" 2>/dev/null || echo "tokens: unknown"
-
Determine gate verdict by checking the review output for critical findings. If the output contains
[P1]— the gate is FAIL. If no[P1]markers are found (only[P2]or no findings) — the gate is PASS. -
Present the output:
CODEX SAYS (code review):
════════════════════════════════════════════════════════════
<full codex output, verbatim — do not truncate or summarize>
════════════════════════════════════════════════════════════
GATE: PASS Tokens: 14,331 | Est. cost: ~$0.12
or
GATE: FAIL (N critical findings)
- Cross-model comparison: If
/review(Claude's own review) was already run earlier in this conversation, compare the two sets of findings:
CROSS-MODEL ANALYSIS:
Both found: [findings that overlap between Claude and Codex]
Only Codex found: [findings unique to Codex]
Only Claude found: [findings unique to Claude's /review]
Agreement rate: X% (N/M total unique findings overlap)
- Persist the review result:
${GSTACK_OPENCODE_DIR}/bin/gstack-review-log '{"skill":"codex-review","timestamp":"TIMESTAMP","status":"STATUS","gate":"GATE","findings":N,"findings_fixed":N}'
Substitute: TIMESTAMP (ISO 8601), STATUS ("clean" if PASS, "issues_found" if FAIL), GATE ("pass" or "fail"), findings (count of [P1] + [P2] markers), findings_fixed (count of findings that were addressed/fixed before shipping).
- Clean up temp files:
rm -f "$TMPERR"
Plan File Review Report
After displaying the Review Readiness Dashboard in conversation output, also update the plan file itself so review status is visible to anyone reading the plan.
Detect the plan file
- Check if there is an active plan file in this conversation (the host provides plan file paths in system messages — look for plan file references in the conversation context).
- If not found, skip this section silently — not every review runs in plan mode.
Generate the report
Read the review log output you already have from the Review Readiness Dashboard step above. Parse each JSONL entry. Each skill logs different fields:
- plan-ceo-review: `status`, `unresolved`, `critical_gaps`, `mode`, `scope_proposed`, `scope_accepted`, `scope_deferred`, `commit` → Findings: "{scope_proposed} proposals, {scope_accepted} accepted, {scope_deferred} deferred" → If scope fields are 0 or missing (HOLD/REDUCTION mode): "mode: {mode}, {critical_gaps} critical gaps"
- plan-eng-review: `status`, `unresolved`, `critical_gaps`, `issues_found`, `mode`, `commit` → Findings: "{issues_found} issues, {critical_gaps} critical gaps"
- plan-design-review: `status`, `initial_score`, `overall_score`, `unresolved`, `decisions_made`, `commit` → Findings: "score: {initial_score}/10 → {overall_score}/10, {decisions_made} decisions"
- codex-review: `status`, `gate`, `findings`, `findings_fixed` → Findings: "{findings} findings, {findings_fixed}/{findings} fixed"
All fields needed for the Findings column are now present in the JSONL entries. For the review you just completed, you may use richer details from your own Completion Summary. For prior reviews, use the JSONL fields directly — they contain all required data.
Produce this markdown table:
```markdown
GSTACK REVIEW REPORT
| Review | Trigger | Why | Runs | Status | Findings |
|---|---|---|---|---|---|
| CEO Review | `/plan-ceo-review` | Scope & strategy | {runs} | {status} | {findings} |
| Codex Review | `/codex review` | Independent 2nd opinion | {runs} | {status} | {findings} |
| Eng Review | `/plan-eng-review` | Architecture & tests (required) | {runs} | {status} | {findings} |
| Design Review | `/plan-design-review` | UI/UX gaps | {runs} | {status} | {findings} |
| ``` |
Below the table, add these lines (omit any that are empty/not applicable):
- CODEX: (only if codex-review ran) — one-line summary of codex fixes
- CROSS-MODEL: (only if both Claude and Codex reviews exist) — overlap analysis
- UNRESOLVED: total unresolved decisions across all reviews
- VERDICT: list reviews that are CLEAR (e.g., "CEO + ENG CLEARED — ready to implement"). If Eng Review is not CLEAR and not skipped globally, append "eng review required".
Write to the plan file
PLAN MODE EXCEPTION — ALWAYS RUN: This writes to the plan file, which is the one file you are allowed to edit in plan mode. The plan file review report is part of the plan's living status.
- Search the plan file for a `## GSTACK REVIEW REPORT` section anywhere in the file (not just at the end — content may have been added after it).
- If found, replace it entirely using the Edit tool. Match from `## GSTACK REVIEW REPORT` through either the next `## ` heading or end of file, whichever comes first. This ensures content added after the report section is preserved, not eaten. If the Edit fails (e.g., concurrent edit changed the content), re-read the plan file and retry once.
- If no such section exists, append it to the end of the plan file.
- Always place it as the very last section in the plan file. If it was found mid-file, move it: delete the old location and append at the end.
Step 2B: Challenge (Adversarial) Mode
Codex tries to break your code — finding edge cases, race conditions, security holes, and failure modes that a normal review would miss.
- Construct the adversarial prompt. If the user provided a focus area
(e.g.,
/codex challenge security), include it:
Default prompt (no focus):
"Review the changes on this branch against the base branch. Run git diff origin/<base> to see the diff. Your job is to find ways this code will fail in production. Think like an attacker and a chaos engineer. Find edge cases, race conditions, security holes, resource leaks, failure modes, and silent data corruption paths. Be adversarial. Be thorough. No compliments — just the problems."
With focus (e.g., "security"):
"Review the changes on this branch against the base branch. Run git diff origin/<base> to see the diff. Focus specifically on SECURITY. Your job is to find every way an attacker could exploit this code. Think about injection vectors, auth bypasses, privilege escalation, data exposure, and timing attacks. Be adversarial."
- Run codex exec with JSONL output to capture reasoning traces and tool calls (5-minute timeout):
codex exec "<prompt>" -s read-only -c 'model_reasoning_effort="xhigh"' --enable web_search_cached --json 2>/dev/null | python3 -c "
import sys, json
for line in sys.stdin:
line = line.strip()
if not line: continue
try:
obj = json.loads(line)
t = obj.get('type','')
if t == 'item.completed' and 'item' in obj:
item = obj['item']
itype = item.get('type','')
text = item.get('text','')
if itype == 'reasoning' and text:
print(f'[codex thinking] {text}')
print()
elif itype == 'agent_message' and text:
print(text)
elif itype == 'command_execution':
cmd = item.get('command','')
if cmd: print(f'[codex ran] {cmd}')
elif t == 'turn.completed':
usage = obj.get('usage',{})
tokens = usage.get('input_tokens',0) + usage.get('output_tokens',0)
if tokens: print(f'\ntokens used: {tokens}')
except: pass
"
This parses codex's JSONL events to extract reasoning traces, tool calls, and the final
response. The [codex thinking] lines show what codex reasoned through before its answer.
- Present the full streamed output:
CODEX SAYS (adversarial challenge):
════════════════════════════════════════════════════════════
<full output from above, verbatim>
════════════════════════════════════════════════════════════
Tokens: N | Est. cost: ~$X.XX
Step 2C: Consult Mode
Ask Codex anything about the codebase. Supports session continuity for follow-ups.
- Check for existing session:
cat .context/codex-session-id 2>/dev/null || echo "NO_SESSION"
If a session file exists (not NO_SESSION), use question:
You have an active Codex conversation from earlier. Continue it or start fresh?
A) Continue the conversation (Codex remembers the prior context)
B) Start a new conversation
- Create temp files:
TMPRESP=$(mktemp /tmp/codex-resp-XXXXXX.txt)
TMPERR=$(mktemp /tmp/codex-err-XXXXXX.txt)
- Plan review auto-detection: If the user's prompt is about reviewing a plan,
or if plan files exist and the user said
/codexwith no arguments:
ls -t ~/.claude/plans/*.md 2>/dev/null | xargs grep -l "$(basename $(pwd))" 2>/dev/null | head -1
If no project-scoped match, fall back to ls -t ~/.claude/plans/*.md 2>/dev/null | head -1
but warn: "Note: this plan may be from a different project — verify before sending to Codex."
Read the plan file and prepend the persona to the user's prompt:
"You are a brutally honest technical reviewer. Review this plan for: logical gaps and
unstated assumptions, missing error handling or edge cases, overcomplexity (is there a
simpler approach?), feasibility risks (what could go wrong?), and missing dependencies
or sequencing issues. Be direct. Be terse. No compliments. Just the problems.
THE PLAN: "
- Run codex exec with JSONL output to capture reasoning traces (5-minute timeout):
For a new session:
codex exec "<prompt>" -s read-only -c 'model_reasoning_effort="xhigh"' --enable web_search_cached --json 2>"$TMPERR" | python3 -c "
import sys, json
for line in sys.stdin:
line = line.strip()
if not line: continue
try:
obj = json.loads(line)
t = obj.get('type','')
if t == 'thread.started':
tid = obj.get('thread_id','')
if tid: print(f'SESSION_ID:{tid}')
elif t == 'item.completed' and 'item' in obj:
item = obj['item']
itype = item.get('type','')
text = item.get('text','')
if itype == 'reasoning' and text:
print(f'[codex thinking] {text}')
print()
elif itype == 'agent_message' and text:
print(text)
elif itype == 'command_execution':
cmd = item.get('command','')
if cmd: print(f'[codex ran] {cmd}')
elif t == 'turn.completed':
usage = obj.get('usage',{})
tokens = usage.get('input_tokens',0) + usage.get('output_tokens',0)
if tokens: print(f'\ntokens used: {tokens}')
except: pass
"
For a resumed session (user chose "Continue"):
codex exec resume <session-id> "<prompt>" -s read-only -c 'model_reasoning_effort="xhigh"' --enable web_search_cached --json 2>"$TMPERR" | python3 -c "
<same python streaming parser as above>
"
- Capture session ID from the streamed output. The parser prints
SESSION_ID:<id>from thethread.startedevent. Save it for follow-ups:
mkdir -p .context
Save the session ID printed by the parser (the line starting with SESSION_ID:)
to .context/codex-session-id.
- Present the full streamed output:
CODEX SAYS (consult):
════════════════════════════════════════════════════════════
<full output, verbatim — includes [codex thinking] traces>
════════════════════════════════════════════════════════════
Tokens: N | Est. cost: ~$X.XX
Session saved — run /codex again to continue this conversation.
- After presenting, note any points where Codex's analysis differs from your own understanding. If there is a disagreement, flag it: "Note: Claude Code disagrees on X because Y."
Model & Reasoning
Model: No model is hardcoded — codex uses whatever its current default is (the frontier
agentic coding model). This means as OpenAI ships newer models, /codex automatically
uses them. If the user wants a specific model, pass -m through to codex.
Reasoning effort: All modes use xhigh — maximum reasoning power. When reviewing code, breaking code, or consulting on architecture, you want the model thinking as hard as possible.
Web search: All codex commands use --enable web_search_cached so Codex can look up
docs and APIs during review. This is OpenAI's cached index — fast, no extra cost.
If the user specifies a model (e.g., /codex review -m gpt-5.1-codex-max
or /codex challenge -m gpt-5.2), pass the -m flag through to codex.
Cost Estimation
Parse token count from stderr. Codex prints tokens used\nN to stderr.
Display as: Tokens: N
If token count is not available, display: Tokens: unknown
Error Handling
- Binary not found: Detected in Step 0. Stop with install instructions.
- Auth error: Codex prints an auth error to stderr. Surface the error:
"Codex authentication failed. Run
codex loginin your terminal to authenticate via ChatGPT." - Timeout: If the Bash call times out (5 min), tell the user: "Codex timed out after 5 minutes. The diff may be too large or the API may be slow. Try again or use a smaller scope."
- Empty response: If
$TMPRESPis empty or doesn't exist, tell the user: "Codex returned no response. Check stderr for errors." - Session resume failure: If resume fails, delete the session file and start fresh.
Important Rules
- Never modify files. This skill is read-only. Codex runs in read-only sandbox mode.
- Present output verbatim. Do not truncate, summarize, or editorialize Codex's output before showing it. Show it in full inside the CODEX SAYS block.
- Add synthesis after, not instead of. Any Claude commentary comes after the full output.
- 5-minute timeout on all Bash calls to codex (
timeout: 300000). - No double-reviewing. If the user already ran
/review, Codex provides a second independent opinion. Do not re-run Claude Code's own review.