codex-skill

# Codex

You are operating in **codex exec** - a non-interactive automation mode for hands-off task execution.

## Prerequisites

Before using this skill, ensure Codex CLI is installed and configured:

1. **Installation verification**:

   ```bash
   codex --version
   ```

2. **First-time setup**: If not installed, guide the user to install Codex CLI with command `npm i -g @openai/codex` or `brew install codex`.

## Core Principles

### Autonomous Execution

- Execute tasks from start to finish without seeking approval for each action
- Make confident decisions based on best practices and task requirements
- Only ask questions if critical information is genuinely missing
- Prioritize completing the workflow over explaining every step

### Output Behavior

- Stream progress updates as you work
- Provide a clear, structured final summary upon completion
- Focus on actionable results and metrics over lengthy explanations
- Report what was done, not what could have been done

### Operating Modes

Codex uses sandbox policies to control what operations are permitted:

**Read-Only Mode (Default)**

- Analyze code, search files, read documentation
- Provide insights, recommendations, and execution plans
- No modifications to the codebase
- **This is the default mode when running `codex exec`**

**Workspace-Write Mode (Recommended for Programming)**

- Read and write files within the workspace
- Implement features, fix bugs, refactor code
- Create, modify, and delete files in the workspace
- Execute build commands and tests
- **Use `--full-auto` or `-s workspace-write` to enable file editing**
- **This is the recommended mode for most programming tasks**

**Danger-Full-Access Mode**

- All workspace-write capabilities
- Network access for fetching dependencies
- System-level operations outside workspace
- Access to all files on the system
- **Use only when explicitly requested and necessary**
- Use flag: `-s danger-full-access`

## Codex CLI Commands

### Model Selection

Codex uses the model configured in `~/.codex/config.toml` by default. Do NOT pass `-m`/`--model` unless the user explicitly asks to use a specific model.

```bash
# Default: uses model from config.toml (recommended)
codex exec --full-auto "refactor the payment processing module"

# Only when user specifies a model explicitly:
codex exec -m gpt-5.2 --full-auto "implement the user authentication feature"
```

### Sandbox Modes

Control execution permissions with `-s` or `--sandbox` (possible values: read-only, workspace-write, danger-full-access):

#### Read-Only Mode

```bash
codex exec "analyze the codebase structure and count lines of code"
codex exec -s read-only "review code quality and suggest improvements"
```

Analyze code without making any modifications.

#### Workspace-Write Mode (Recommended for Programming)

```bash
codex exec -s workspace-write "implement the user authentication feature"
codex exec --full-auto "fix the bug in login flow"
```

Read and write files within the workspace. **Must be explicitly enabled (not the default). Use this for most programming tasks.**

#### Danger-Full-Access Mode

```bash
codex exec -s danger-full-access "install dependencies and update the API integration"
```

Network access and system-level operations. Use only when necessary.

### Full-Auto Mode (Convenience Alias)

```bash
codex exec --full-auto "implement the user authentication feature"
```

**Convenience alias for**: `-s workspace-write` (enables file editing).
This is the **recommended command for most programming tasks** since it allows codex to make changes to your codebase.

### Config Overrides

Override any `config.toml` value inline with `-c` or `--config`:

```bash
# Override model for a single run
codex exec -c model="o3" --full-auto "implement the feature"

# Override sandbox permissions
codex exec -c 'sandbox_permissions=["disk-full-read-access"]' "analyze all files"

# Override nested config values using dotted paths
codex exec -c shell_environment_policy.inherit=all --full-auto "run build"
```

### Feature Toggles

Enable or disable features with `--enable` and `--disable`:

```bash
codex exec --enable multi_agent --full-auto "implement feature across multiple files"
codex exec --disable plan_tool --full-auto "quick fix for typo"
```

Equivalent to `-c features.<name>=true` or `-c features.<name>=false`.

### Image Attachments

Attach images to the prompt with `-i` or `--image`:

```bash
codex exec -i screenshot.png "implement the UI shown in this screenshot"
codex exec -i mockup.png -i spec.png --full-auto "build this component matching the design"
```

### Code Review

Run code reviews with `codex exec review`:

```bash
# Review uncommitted changes (staged, unstaged, and untracked)
codex exec review --uncommitted

# Review changes against a base branch
codex exec review --base main

# Review a specific commit
codex exec review --commit abc1234

# Custom review instructions
codex exec review --base main "focus on security vulnerabilities and error handling"

# Review with a title for the summary
codex exec review --base main --title "Auth feature review"

# Output review as JSON
codex exec review --uncommitted --json -o review.json
```

### Configuration Profiles

Use saved profiles from `~/.codex/config.toml` with `-p` or `--profile`:

```bash
codex exec -p production "deploy the latest changes"
codex exec --profile development "run integration tests"
```

Profiles can specify default model, sandbox mode, and other options.

### Working Directory

Specify a different working directory with `-C` or `--cd`:

```bash
codex exec -C /path/to/project --full-auto "implement the feature"
codex exec --cd ~/projects/myapp --full-auto "run tests and fix failures"
```

### Additional Writable Directories

Allow writing to additional directories outside the main workspace with `--add-dir`:

```bash
codex exec --full-auto --add-dir /tmp/output --add-dir ~/shared "generate reports in multiple locations"
```

### JSON Out