Model Context Protocol

For the complete documentation index, see llms.txt. Markdown versions of documentation pages are available by appending .md to the page URL.

Model Context Protocol (MCP) connects models to tools and context. Use it to give ChatGPT or Codex access to third-party documentation, or to let it interact with developer tools like your browser or Figma.

ChatGPT web can use remote MCP-backed tools supplied by plugins. Local Codex clients can also connect directly to MCP servers and share their configuration.

The ChatGPT desktop app, Codex CLI, and IDE extension support MCP servers and share MCP configuration for the same Codex host.

The supported server features below apply to MCP servers configured on a Codex host. Hosted plugin tools can have different capabilities.

Supported MCP features

• STDIO servers: Servers that run as a local process (started by a command).
  • Environment variables
• Streamable HTTP servers: Servers that you access at an address.
  • Bearer token authentication
  • OAuth authentication, including Client ID Metadata Documents (CIMD) and Dynamic Client Registration (DCR)
  • ChatGPT session authentication for trusted first-party servers
• Server instructions: Codex reads the MCP instructions field returned during initialization and uses it as server-wide guidance alongside the server's tools.

If you build or maintain an MCP server for Codex, use instructions for cross-tool workflows, constraints, and rate limits that apply across the server. Keep the first 512 characters self-contained so the most important guidance is available when Codex is deciding how to use the server.

Connect Codex to an MCP server

Codex stores MCP configuration in config.toml alongside other Codex configuration settings. By default this is ~/.codex/config.toml, but you can also scope MCP servers to a project with .codex/config.toml (trusted projects only).

The ChatGPT desktop app, Codex CLI, and IDE extension share this configuration. Once you configure your MCP servers, you can switch among those clients without redoing setup.

Configure in the ChatGPT desktop app

1. Open Settings, then select MCP servers.
2. Select Add server.
3. Enter a name, choose STDIO or Streamable HTTP, and provide the server's command or URL.
4. Save the server, then select Restart.

The server list shows which servers are enabled and which require OAuth. Select Authenticate when an OAuth server requires sign-in. In the composer, type /mcp to view connected servers.

Use MCP-backed tools in ChatGPT web

In a hosted ChatGPT Work chat, install a plugin to use its bundled connectors and remote MCP tools. After installation, Chat and Work can use those tools. Workspace administrators can control which plugins and tools are available.

ChatGPT web doesn't read local Codex configuration files or expose the local Codex command menu. Open the Plugins tab to browse and manage available tools.

Configure with the CLI

Add an MCP server