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name: codex description: Use when the user asks to run Codex CLI (codex exec, codex resume) or references OpenAI Codex for code analysis, refactoring, or automated editing

Codex Skill Guide

Running a Task

1. Ask the user (via AskUserQuestion) which model to run (gpt-5.2-codex or gpt-5.2) AND which reasoning effort to use (xhigh, high, medium, or low) in a single prompt with two questions.
2. Select the sandbox mode required for the task; default to --sandbox read-only unless edits or network access are necessary.
3. Assemble the command with the appropriate options:
   • -m, --model <MODEL>
   • --config model_reasoning_effort="<xhigh|high|medium|low>"
   • --sandbox <read-only|workspace-write|danger-full-access>
   • --full-auto
   • -C, --cd <DIR>
   • --skip-git-repo-check
4. Always use --skip-git-repo-check.
5. When continuing a previous session, use codex exec --skip-git-repo-check resume --last via stdin. When resuming don't use any configuration flags unless explicitly requested by the user e.g. if he species the model or the reasoning effort when requesting to resume a session. Resume syntax: echo "your prompt here" | codex exec --skip-git-repo-check resume --last 2>/dev/null. All flags have to be inserted between exec and resume.
6. IMPORTANT: By default, append 2>/dev/null to all codex exec commands to suppress thinking tokens (stderr). Only show stderr if the user explicitly requests to see thinking tokens or if debugging is needed.
7. Run the command, capture stdout/stderr (filtered as appropriate), and summarize the outcome for the user.
8. After Codex completes, inform the user: "You can resume this Codex session at any time by saying 'codex resume' or asking me to continue with additional analysis or changes."

Quick Reference

| Use case | Sandbox mode | Key flags | | --- | --- | --- | | Read-only review or analysis | | | | Apply local edits | | | | Permit network or broad access | | | | Resume recent session | Inherited from original | (no flags allowed) | | Run from another directory | Match task needs | plus other flags |

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Codex Integration for Claude Code

<img width="2288" height="808" alt="skillcodex" src="https://github.com/user-attachments/assets/85336a9f-4680-479e-b3fe-d6a68cadc051" />

Purpose

Enable Claude Code to invoke the Codex CLI (codex exec and session resumes) for automated code analysis, refactoring, and editing workflows.

Prerequisites

• codex CLI installed and available on PATH.
• Codex configured with valid credentials and settings.
• Confirm the installation by running codex --version; resolve any errors before using the skill.

Installation

Download this repo and store the skill in ~/.claude/skills/codex

git clone --depth 1 git@github.com:skills-directory/skill-codex.git /tmp/skills-temp && \
mkdir -p ~/.claude/skills && \
cp -r /tmp/skills-temp/ ~/.claude/skills/codex && \
rm -rf /tmp/skills-temp

Usage

Important: Thinking Tokens

By default, this skill suppresses thinking tokens (stderr output) using 2>/dev/null to avoid bloating Claude Code's context window. If you want to see the thinking tokens for debugging or insight into Codex's reasoning process, explicitly ask Claude to show them.

Example Workflow

User prompt:

Use codex to analyze this repository and suggest improvements for my claude code skill.

Claude Code response: Claude will activate the Codex skill and:

1. Ask which model to use (gpt-5 or gpt-5-codex) unless already specified in your prompt.
2. Ask which reasoning effort level (, , or ) unless already specified in your prompt.