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FreeCAD AI Modeling Guide

Codex CLI

OpenAI’s terminal coding tool. The cadxray bridge is standard MCP, so it connects with the same command. What differs is the registration command, the rules file name (AGENTS.md), and whether screenshots are displayed.

Install

Section titled “Install”

Install and sign in to Codex CLI following OpenAI’s instructions. Check:

터미널 창
codex --version

Register

Section titled “Register”
Terminal
codex mcp add cadxray -- uvx --from git+https://github.com/WaveSimm/cadxray#subdirectory=bridge cadxray

Or write it into ~/.codex/config.toml directly (on Windows, C:\Users\<name>\.codex\config.toml).

~/.codex/config.toml
[mcp_servers.cadxray]
command = "uvx"
args = ["--from", "git+https://github.com/WaveSimm/cadxray#subdirectory=bridge", "cadxray"]

If you changed the port, append "--port", "9878" to args. If Windows cannot find uvx, put the full path (the output of (Get-Command uvx).Source) in command.

Check the connection

Section titled “Check the connection”
터미널 창
codex mcp list

Seeing cadxray is enough. With FreeCAD running, open codex and start.

Say this
Check whether cadxray can reach FreeCAD and tell me the version.

The rules file — AGENTS.md

Section titled “The rules file — AGENTS.md”

Codex reads AGENTS.md from the working folder. Save cadxray’s CLAUDE.md under that name and it follows the same instructions.

Terminal
mkdir C:\cad-work
cd C:\cad-work
curl -o AGENTS.md https://raw.githubusercontent.com/WaveSimm/cadxray/master/CLAUDE.md
codex

Leave the mentions of “Claude” inside the file alone. The tool names and the order matter; what the assistant is called does not. You can delete the developer rules at the top (milestones, commits, tests).

What is different about this tool

Section titled “What is different about this tool”
  • Screenshots: whether Codex renders images returned by MCP in the chat depends on the version. If they do not show, look at the FreeCAD window. The numbers (volume, degrees of freedom, safety factor) come back as text, so nothing is lost for verification.
  • Approvals: Codex may ask for approval on every tool call. During a modeling session it is easier to leave it on auto-approve — the AI will not save files until you tell it to anyway.
  • The prompts are identical to Claude Code’s. Writing prompts applies to all three tools.

Checklist

Section titled “Checklist”
Command What you should see
Registered codex mcp list cadxray
Connected first conversation FreeCAD 1.1.3, 36 tools
Rules working folder AGENTS.md present