What this does

Codex looks for Model Context Protocol servers in ~/.codex/config.toml. Adding the Chrome DevTools block lets Codex launch a dedicated Chrome instance with the correct debugging flags whenever a DevTools task runs.

Steps

Ensure ~/.codex/config.toml exists (create the directory/file if needed).
Append the Chrome DevTools MCP block shown above.
Restart Codex so the new server definition is loaded.

Verification

After Codex restarts, ask it to run a browser task such as:

Check the LCP of https://web.dev

Codex should spawn a Chrome window controlled through MCP and return a response. You can also target a local project:

Open http://localhost:3000 and report console errors

Variations

To add more MCP servers, repeat the pattern with another [mcp_servers."name"] block.
If the Chrome window fails to launch automatically, manually start Chrome with --remote-debugging-port=9222 and rerun the command.

Safety Notes

Non-destructive: only edits your Codex configuration file.
Expect a separate Chrome profile window when the MCP server starts.

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Codex: add Chrome DevTools MCP via config.toml