Codex MCP Server

Bridge between Claude and OpenAI's Codex CLI — get AI-powered code analysis, generation, and review right in your editor.

Quick Start

1. Install Codex CLI

npm i -g @openai/codex
codex login --api-key "your-openai-api-key"

2. Add to Claude Code

claude mcp add codex-cli -- npx -y codex-mcp-server

3. Start Using

Ask codex to explain this function
Use codex to refactor this code for better performance
Use review to check my uncommitted changes

One-Click Install

Tools

Tool	Description
codex	AI coding assistant with session support, model selection, and structured output metadata
review	AI-powered code review for uncommitted changes, branches, or commits
websearch	Web search using Codex CLI with customizable result count and search depth
listSessions	View active conversation sessions
ping	Test server connection
help	Get Codex CLI help

Examples

Code analysis:

Use codex to analyze this authentication logic for security issues

Multi-turn conversations:

Use codex with sessionId "refactor" to analyze this module
Use codex with sessionId "refactor" to implement your suggestions

Passing a sessionId creates the session on first use, so listSessions will show it (for this server instance) and subsequent calls can resume context.

Code review:

Use review with base "main" to check my PR changes
Use review with uncommitted true to review my local changes

Advanced options:

Use codex with model "o3" and reasoningEffort "high" for complex analysis
Use codex with fullAuto true and sandbox "workspace-write" for automated tasks
Use codex with callbackUri "http://localhost:1234/callback" for static callbacks
Use codex to return structuredContent with threadId metadata when available

Web search:

Use websearch with query "TypeScript 5.8 new features"
Use websearch with query "Rust vs Go performance 2025" and numResults 15
Use websearch with query "React Server Components" and searchDepth "full"

Requirements

• Codex CLI v0.75.0+ — Install with npm i -g @openai/codex or brew install codex

• OpenAI API key — Run codex login --api-key "your-key" to authenticate

Codex 0.87 Compatibility

• Thread ID + structured output: When Codex CLI emits threadId, this server returns it in content metadata and structuredContent, and advertises an outputSchema for structured responses.

Documentation

• API Reference — Full tool parameters and response formats

• Session Management — How conversations work

• Codex CLI Integration — Version compatibility and CLI details

Environment Variables

• CODEX_MCP_CALLBACK_URI: Static MCP callback URI passed to Codex when set (overridden by callbackUri tool arg)

Development

npm install    # Install dependencies
npm run dev    # Development mode
npm run build  # Build for production
npm test       # Run tests

Related Projects

• gemini-mcp-server — MCP server for Gemini CLI with 1M+ token context, web search, and media analysis

License

ISC