codex-cli

# OpenAI Codex CLI Skill

Use OpenAI Codex CLI (`codex`) for coding tasks including code review, refactoring, bug fixes, CI repairs, and feature implementation. Codex CLI runs locally on your machine with full filesystem access.

## When to Use

- User asks for code changes, refactoring, or implementation
- CI/build failures need fixing
- Code review before commit/push
- Large codebase exploration or explanation
- Tasks requiring file editing + command execution
- When GPT-5-Codex model strengths are needed (code generation, tool use)

## Installation & Auth

Codex CLI requires ChatGPT Plus/Pro/Business/Enterprise subscription.

```bash
# Install
npm i -g @openai/codex

# Authenticate (opens browser for OAuth)
codex login

# Or use API key
printenv OPENAI_API_KEY | codex login --with-api-key

# Verify auth
codex login status
```

## Core Commands

### Interactive Mode (TUI)
```bash
codex                           # Launch interactive terminal UI
codex "explain this codebase"   # Start with a prompt
codex --cd ~/projects/myapp     # Set working directory
```

### Non-Interactive (Scripting)
```bash
codex exec "fix the CI failure"                    # Run and exit
codex exec --full-auto "add input validation"      # Auto-approve workspace writes
codex exec --json "list all API endpoints"         # JSON output for parsing
codex exec -i screenshot.png "match this design"   # With image input
```

### Session Management
```bash
codex resume               # Pick from recent sessions
codex resume --last        # Continue most recent
codex resume <SESSION_ID>  # Resume specific session
```

## Slash Commands (In TUI)

| Command | Purpose |
|---------|---------|
| `/model` | Switch model (gpt-5-codex, gpt-5) |
| `/approvals` | Set approval mode (Auto, Read Only, Full Access) |
| `/review` | Code review against branch, uncommitted changes, or specific commit |
| `/diff` | Show Git diff including untracked files |
| `/compact` | Summarize conversation to free context |
| `/ini...