Install Neo4j Canary in Codex

What you need first

• Codex, installed.
• uv, which gives the uvx command the server starts with.
• Your own values for YOUR_NEO4J_URI,YOUR_NEO4J_USERNAME,YOUR_NEO4J_PASSWORD,YOUR_NEO4J_DATABASE.

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 neo4j-mcp-canary --env NEO4J_URI=YOUR_NEO4J_URI --env NEO4J_USERNAME=YOUR_NEO4J_USERNAME --env NEO4J_PASSWORD=YOUR_NEO4J_PASSWORD --env NEO4J_DATABASE=YOUR_NEO4J_DATABASE -- uvx neo4j-mcp-canary==0.2.3

2. Replace YOUR_NEO4J_URI,YOUR_NEO4J_USERNAME,YOUR_NEO4J_PASSWORD,YOUR_NEO4J_DATABASE with your own values.
3. Start Codex again and type /mcp: the server is listed.

Check it worked

Ask Codex: List the tools of neo4j-mcp-canary.

If it does not start

spawn uvx ENOENT

uv is not on the PATH that Codex sees. Install it, or write the full path of uvx in the config.

The server starts, but its tools fail

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