codex-agent

A Claude Code plugin that delegates coding tasks to OpenAI's Codex CLI as a fast build agent. Codex runs non-interactively using gpt-5.3-codex-spark at ~1,000 tokens/sec with configurable reasoning levels.

Features

• Skill — Full documentation for using Codex as a build agent, loaded automatically when relevant
• /codex command — Quick delegation: /codex add JSDoc to lib/utils.ts
• Autonomous agent — Detects mechanical tasks and suggests Codex delegation

Prerequisites

• OpenAI Codex CLI installed: npm install -g @openai/codex
• OPENAI_API_KEY set in your environment

Installation

# Add the marketplace
claude plugin marketplace add dennisonbertram/codex-agent

# Install the plugin
claude plugin install codex-agent

Usage

Slash Command

/codex add "use client" directive to components/dashboard.tsx
/codex --reasoning=high analyze the auth flow in middleware.ts
/codex --read-only count how many API routes exist

Skill (automatic)

The skill loads automatically when you mention "codex", "delegate to codex", "use codex agent", or discuss parallel task execution. It provides Claude with full knowledge of Codex CLI flags, reasoning levels, and prompt patterns.

Agent (autonomous)

The codex-delegator agent triggers when you ask to delegate mechanical tasks:

• "use codex to add types to these files"
• "have codex handle the boilerplate generation"
• "delegate the JSDoc additions to codex"

Reasoning Levels

Control how much Codex "thinks" before acting:

Components

codex-agent/
├── .claude-plugin/
│   └── marketplace.json         # Marketplace manifest
├── README.md                    # This file
├── plugins/
│   └── codex-agent/
│       ├── .claude-plugin/
│       │   └── plugin.json      # Plugin manifest
│       ├── skills/
│       │   └── codex-agent/
│       │       └── SKILL.md     # Codex build agent knowledge
│       ├── commands/
│       │   └── codex.md         # /codex slash command
│       └── agents/
│           └── codex-delegator.md  # Autonomous delegation agent

License

MIT