Install Explicit Formula — Second Brain in Codex

What you need first

• Codex, installed.
• Node.js, which gives the npx command the server starts with.
• Your own value for YOUR__ABSOLUTE_PATH_TO_YOURVAULT.

Steps

1. Run this in a terminal. It writes the server into ~/.codex/config.toml, which the Codex CLI, its IDE extension and the ChatGPT desktop app share.

codex mcp add second-brain -- npx -y @travisbergen2/[email protected] --vault YOUR__ABSOLUTE_PATH_TO_YOURVAULT

2. Replace YOUR__ABSOLUTE_PATH_TO_YOURVAULT with your own value.
3. Start Codex again and type /mcp: the server is listed.

Check it worked

Ask Codex: List the tools of second-brain.

If it does not start

spawn npx ENOENT

Node.js is not on the PATH that Codex sees. Install it, or write the full path of npx in the config.

The server starts, but its tools fail

A YOUR_… placeholder is still in the config, or its value is wrong.