Set up MCP servers in Codex CLI

Which configuration file format Codex CLI reads, what it is called and where it belongs – from the vendor’s own documentation, with source and collection date.

Location

Source: learn.chatgpt.com/docs/extend/mcp?surface=cli, retrieved on 2026-08-27

The root key

A file with the wrong root key is read and does nothing – without an error message. That is why the format is stated here next to the location.

Other clients read a different format: Claude Desktop, Claude Code, Cursor, Visual Studio Code, Windsurf. All clients side by side

Build a configuration for Codex CLI

The builder forms the block from the registry data of a chosen server and prints it in exactly the format Codex CLI reads.

Build a configuration for Codex CLI

What the builder can produce a file for

12,154 of the 26,983 published entries carry a package coordinate from which a published start template forms a block. The remaining 14,829 name no package or a source without a published template; for those the builder produces nothing and says why.

What is NOT stated here

This registry holds no statement about which server works with which client. No manifest declares a client list, and the registry invents none. What is stated here is the file format and its location according to the client’s own documentation – not a claim about a server.

Client knowledge version: 1

tracevero · https://tracevero.com/klient/codex