Codex

TOML rather than JSON, so the app merges one section instead of writing one key.

Connect it

In the app, register with Codex. It writes into ~/.codex/config.toml, under mcp_servers.

Why this one is different

Claude Code and Cursor both use JSON, where replacing one key is unambiguous. Codex uses TOML, which has no single canonical way to represent the same document, so a naive write that parsed the file and re-serialised it would reformat everything you had in there, reorder your sections and drop your comments.

So the app does not do that. It merges its own section and leaves the rest of the file as the bytes it found, comments and all.

What has and has not been proven

Codex is not the path this was developed against. Registration is verified; live editing has not had the hours Claude Code has. The app says so on its agent screen.

Removing it

Unregistering takes the section out again and leaves the rest of the file byte-identical. That case is tested on every release, because a tool that makes a mess when you remove it is a tool people are right not to install.