Add a local MCP server to Codex
mcp & extensions
// what it does
codex mcp add registers a stdio MCP server. Everything after the -- separator is the command Codex launches to talk to the server; pass server environment variables with --env before the --. The command writes a [mcp_servers.NAME] block into ~/.codex/config.toml.
// shell
$ codex mcp add context7 -- npx -y @upstash/context7-mcp$ codex mcp add myserver --env API_TOKEN=abc123 -- npx my-mcp-server// gotcha
The -- separator matters: flags after it belong to the server command, flags before it (like --env) belong to codex. Omit it and codex tries to parse the server's own arguments as its own.