| name | codex |
| description | Consult OpenAI Codex CLI for a second opinion on plans, tests, code review, and more. Use this skill automatically whenever a second perspective would strengthen your output — especially for architectural plans, code review, test strategy, and debugging. |
| argument-hint | [task] [details...] |
| allowed-tools | Bash(codex *), Bash(codex exec *) |
Runtime Scope
- Use this skill in Claude Code workflows.
- If the active assistant is Codex and this skill is referenced, do not invoke Codex CLI directly; use a subagent for the second-opinion task instead.
Consult the OpenAI Codex CLI as a second-opinion advisor. Use its output to compare, validate, or enrich your own analysis.
User request: $ARGUMENTS
Instructions
Step 1: Determine the consultation type
Based on the user's request, determine which mode applies:
- plan — Ask Codex to propose an implementation plan or architecture
- review — Ask Codex to review specific code for bugs, style, and improvements
- test — Ask Codex to suggest test cases or generate tests for specific code
- explain — Ask Codex to explain how specific code works
- debug — Ask Codex to analyze a bug or error and suggest fixes
- general — Any other consultation
Step 2: Gather context
Before calling Codex, gather relevant context so you can craft a focused prompt:
- Read the files relevant to the user's request
- Check
git diff --stat or git log --oneline -10 if the request involves recent changes
- Understand what specific question or area the user wants Codex's perspective on
Step 3: Call Codex
Run Codex via codex exec in non-interactive mode. Always pass -C with the project directory.
For read-only consultation (review, explain, debug):
codex exec -s read-only "YOUR_PROMPT" -C /path/to/project
For code generation (test, plan with output):
codex exec -s workspace-write "YOUR_PROMPT" -C /path/to/project
For code review specifically:
codex exec review -C /path/to/project
CLI Reference (codex-cli v0.114.0)
| Flag | Description |
|---|
-s read-only | Read-only sandbox — can read files but not modify |
-s workspace-write | Can write to workspace |
-C /path | Set working directory |
-m MODEL | Override model (e.g. -m o3) |
--json | Output events as JSONL |
--ephemeral | Don't persist session files |
-o FILE | Write last message to file |
-c key=value | Override config (e.g. -c model="o3") |
--full-auto | Convenience alias for sandboxed auto-execution |
Do NOT use these (they don't exist):
--quiet — not a valid flag--approval-mode — not a valid flag- Top-level
codex "prompt" for non-interactive — use codex exec instead
Prompt crafting rules
- Include the specific file paths and relevant code context
- Be explicit about what you want: "Review this code for bugs", "Propose a plan to implement X", "Write unit tests for Y"
- Include constraints: "This project uses [framework/language]. Follow existing patterns."
- Keep it focused — one clear ask per invocation
If the output is too large or Codex needs to examine many files, break it into multiple focused calls.
If codex is not installed, tell the user:
Codex CLI is not installed. Install it with: npm install -g @openai/codex
Make sure your OPENAI_API_KEY environment variable is set.
Then stop.
Step 4: Synthesize
Do NOT just dump Codex's raw output. Instead:
- Present Codex's perspective — summarize its key points clearly
- Add your own analysis — where do you agree or disagree? What did it miss? What did it catch that you wouldn't have?
- Highlight conflicts — if Codex's suggestion contradicts the project's existing patterns or the user's preferences, flag it
- Give a recommendation — a clear, unified recommendation combining the best of both perspectives
Format the output as:
Codex Consultation
Query: (what was asked)
Codex's Take
(summarized key points from Codex output)
My Analysis
(where you agree, disagree, or would extend Codex's suggestions)
Conflicts & Caveats
(any contradictions with existing codebase patterns, CLAUDE.md rules, or project conventions)
Recommendation
(unified recommendation — the best path forward considering both perspectives)
Step 5: Offer next steps
Ask the user if they want to:
- Act on the recommendation
- Ask Codex a follow-up question
- Get deeper analysis on a specific point
Keeping This Skill Up To Date
This skill was last verified against codex-cli v0.114.0. If Codex CLI is updated and commands fail, run codex exec --help to check current flags and update this skill accordingly. Common things that change between versions:
- Flag names and aliases
- Sandbox mode values
- Subcommands (e.g.
exec review was added later)
- Default model names
