Codex keeps MCP servers in a TOML file rather than JSON, and remote servers are configured by editing it directly.
Add the server
Open the configuration file
~/.codex/config.toml. Create it if it does not exist.
Note that codex mcp add is documented for stdio servers - the ones Codex launches as a local process. A remote server such as this one goes in the file by hand.
Add Voiceflow
The table name carries the server’s local name, so [mcp_servers.voiceflow] is what produces the voiceflow prefix. url is the only required key.
Sign in
Start Codex and let it connect. It opens a browser to Voiceflow; approve the request and the tab redirects back.
Codex also supports a bearer token read from an environment variable for remote servers. That route does not apply here - Voiceflow issues no static token, and the browser sign-in is the whole of it. See Authentication.
Confirm it worked
Ask Codex to list your Voiceflow projects. A list means the transport, the grant, and your account access are all working.
If it does not connect
To disconnect, delete the [mcp_servers.voiceflow] table. Revoke access in Voiceflow to end every client’s session at once.