Overview

Codex MCP Server is a lightweight, open-source Model Context Protocol (MCP) server that wraps OpenAI's official Codex CLI. It acts as a bridge, allowing MCP clients such as Claude Desktop/Code, Cursor, Windsurf, and others to call Codex as a tool for advanced coding tasks.

This enables hybrid AI workflows where Claude handles high-level reasoning and strategy while delegating heavy code generation, refactoring, analysis, and execution to Codex's powerful GPT-based engine.

Popular community project maintained by tuannvm and others.

Key Features

Full integration with OpenAI Codex CLI capabilities
Exposes Codex commands (explain, refactor, generate, analyze, exec, etc.) as structured MCP tools
Supports codex exec for safe, sandboxed code execution and edits
Streams progress updates and structured patch outputs
Easy one-command installation via npx
Works with both local STDIO and configurable environments
Cross-platform (macOS, Linux, Windows)
Secure approval flows for file modifications

Installation & Setup

Quick Start (for Claude Code)

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

Alternative repositories / forks

https://github.com/tuannvm/codex-mcp-server (primary)
https://github.com/cexll/codex-mcp-server (enhanced version)
Built-in Codex MCP mode: codex mcp-server (native support in recent Codex CLI)

After adding, restart your MCP client and confirm the server appears in the tools list.

Use Cases

Hybrid Agentic Coding: Use Claude for planning and Codex for high-quality code output
Code Review & Refactoring: Ask Claude to review a codebase, then delegate complex refactors to Codex
Debugging Stuck Tasks: When one model gets stuck, hand off to the other via MCP
Large-scale Analysis: Leverage Codex's context window and reasoning on massive projects
Multi-model Orchestration: Combine strengths of Anthropic and OpenAI models in a single workflow
CI/CD Automation and batch code transformations

Requirements

OpenAI Codex CLI installed (npm i -g @openai/codex or Homebrew)
Valid OpenAI API access (Codex uses GPT models)
An MCP-compatible client (Claude Code/Desktop recommended)

Resources

GitHub: https://github.com/tuannvm/codex-mcp-server
Official Codex MCP Documentation: https://developers.openai.com/codex/mcp/
Native Codex as MCP Server: Run codex mcp-server directly

Codex MCP Server is one of the most practical tools for developers wanting to combine the best of Claude's reasoning with Codex's coding prowess in the growing MCP ecosystem.