OpenAI Codex

Codex is OpenAI’s terminal-based AI assistant. It speaks MCP, so once you point it at the Rhino MCP server, it can drive Rhino & Grasshopper the same way Claude can.

If you’re choosing between assistants and aren’t sure, start with Claude Desktop; it’s the gentler entry point.

Before you start

1. The Rhino-MCP-Platform plugin is installed in Rhino. See Getting Started if you haven’t done that yet.
2. Codex is installed and signed in. See the Codex install guide if you need it.

Wire up the Rhino MCP server

1. In Rhino, run the MCPConnect command. It prints the command Codex needs to launch the Rhino MCP router.

2. Open ~/.codex/config.toml (create it if it doesn’t exist).

3. Add an entry for the Rhino server, pasting the command and args from step 1:

   [mcp_servers.rhino]
   command = "rhino-mcp-router"
   args = ["--default-version", "8"]

4. Restart Codex. The rhino server should appear when you list MCP servers from inside a session.

Pick the Rhino version by changing the --default-version arg. Use 8 for Rhino 8, 9 for Rhino 9 WIP.

Try it out

Start a Codex session and follow the prompts on the Try it out page.