A Claude Code plugin that provides a skill for seamless OpenAI Codex CLI integration with GPT-5.2 high-reasoning capabilities.

Philosophy: Codex = Brain (thinking), Claude = Hands (implementation)

cc-skill-codex is a Claude Code plugin that contains the codex skill. When you install this plugin, you get access to the skill that enables Codex CLI integration.

• Marketplace name: cc-skill-codex-marketplace
• Plugin name: cc-skill-codex
• Full plugin identifier: cc-skill-codex@cc-skill-codex-marketplace
• Skill name: codex
• Installation: Via Claude Code marketplace (installs the plugin, which includes the skill)

cc-skill-codex/                  # Plugin root
├── .claude-plugin/              # Plugin metadata
│   ├── plugin.json             # Plugin configuration
│   └── marketplace.json        # Marketplace configuration
├── README.md                    # This file - installation and usage guide
├── LICENSE                      # Apache 2.0 license
└── skills/                      # Skills provided by this plugin
    └── codex/                  # The "codex" skill
        ├── SKILL.md            # Main skill definition (loaded by Claude Code)
        └── references/         # Reference documentation (for users)
            ├── command-patterns.md      # Design → Implementation workflows
            ├── session-workflows.md     # Session continuation patterns
            ├── troubleshooting.md       # Error solutions and debugging
            ├── codex-config.md          # Complete configuration reference
            ├── codex-help.md            # Codex CLI v0.77 help reference
            └── advanced-patterns.md     # Advanced options

How it works:

1. You add the marketplace (cc-skill-codex-marketplace) from GitHub
2. You install the plugin (cc-skill-codex) from the marketplace
3. The plugin provides the skill (codex)
4. Claude Code loads skills/codex/SKILL.md when the skill is invoked
5. All other files are documentation for users

1. Codex CLI installed and authenticated:

   codex --version  # v0.77+
   codex login

2. Claude Code installed and running

1. Add the marketplace to Claude Code:

   /plugin marketplace add wywwzjj/cc-skill-codex

2. Open plugin management:

   /plugin

3. Select "Browse Plugins" to view available plugins

4. Find and select cc-skill-codex

5. Choose the installation option

# 1. Add the marketplace
/plugin marketplace add wywwzjj/cc-skill-codex

# 2. Install the plugin
/plugin install cc-skill-codex@cc-skill-codex-marketplace

After installation, verify the skill is working:

> Use Codex to design a binary search tree in Rust

The skill will invoke Codex CLI with GPT-5.2 high-reasoning capabilities.

# Check if Codex CLI is installed
codex --version  # Requires v0.77+

# If not installed, follow OpenAI's installation instructions
# https://developers.openai.com/codex/cli/installation

# Authenticate with your OpenAI account
codex login

Add the GitHub marketplace to Claude Code:

/plugin marketplace add wywwzjj/cc-skill-codex

This registers the marketplace so Claude Code knows where to find the plugin.

Option A: Interactive Menu (Recommended)

1. Open plugin management:

   /plugin

2. Select "Browse Plugins"

3. Find "cc-skill-codex" and install it

Option B: Direct Command

/plugin install cc-skill-codex@cc-skill-codex-marketplace

Note: The full identifier is cc-skill-codex@cc-skill-codex-marketplace where:

• cc-skill-codex = plugin name
• cc-skill-codex-marketplace = marketplace name (from marketplace.json)

Check the plugin is installed:

/plugin

Select "Manage Plugins" to see cc-skill-codex in your list.

Design request (Codex thinks, Claude implements):

> Use Codex to design a REST API for a blog system

Codex will:

1. Execute: codex exec -m gpt-5.2-codex -s read-only -c model_reasoning_effort=high -c hide_agent_reasoning=true "Design a REST API..."
2. Provide high-level architecture, endpoint design, data models
3. Session auto-saved for continuation

Then implement with Claude:

> Implement the user authentication endpoint based on Codex's design

Claude will implement the code using Codex's design.

Review request:

> Use Codex to review this authentication code for security issues

Codex will:

1. Analyze with high reasoning (read-only mode)
2. Identify vulnerabilities and best practice violations
3. Provide improvement recommendations

Then fix with Claude:

> Fix the security issues in auth.py:45-67 as Codex suggested

Follow-up request:

> Continue with that API - add error handling

Codex will:

1. Execute: codex exec -m gpt-5.2-codex -c hide_agent_reasoning=true resume --last "Add comprehensive error handling to the API"
2. Resume with full context from previous session
3. Build on previous design decisions

Why this matters: Codex sessions persist across Claude Code restarts - you can resume days later with full context.

Debug request:

> Use Codex to analyze why my queue implementation deadlocks under high concurrency

Codex will:

1. Perform deep reasoning analysis
2. Identify root cause and race conditions
3. Suggest debugging approach and fixes

Then implement fix with Claude:

> Apply the fix Codex suggested at lines 23-45

• Codex = Brain: Design, architecture, code review, debug analysis (read-only)
• Claude = Hands: Implementation, refactoring, file modifications

• Explicit: "Use Codex to design...", "Use Codex to review..."
• Keywords: Mention "Codex" to explicitly trigger the skill
• Best practice: Be explicit about what you want Codex to do

• gpt-5.2 (default): General reasoning, architecture design, code review
• gpt-5.2-codex: Code editing tasks (rare - usually let Claude implement)
• Default reasoning: High reasoning effort for maximum quality

• Keywords: "continue", "resume", "add to that", "keep going"
• Persistence: Sessions survive Claude Code restarts
• Long-term context: Resume projects days or weeks later with full history

For detailed information, see:

• skills/codex/SKILL.md - Main skill documentation
• skills/codex/references/command-patterns.md - Design → Implementation workflows
• skills/codex/references/session-workflows.md - Session continuation examples
• skills/codex/references/troubleshooting.md - Error solutions and debugging
• skills/codex/references/codex-config.md - Configuration reference

License: Apache 2.0 Version: 2.0.0 Codex CLI: v0.77+ Philosophy: Codex = Brain (thinking), Claude = Hands (implementation)