Comparing the three tools

What is the same

• The prompts. “A 100×60 plate 5 thick with four Ø6.6 holes” produces the same result in any of them. The «Say this» boxes on this site work as-is in all three.
• The FreeCAD side. You install the addon (the first command) once. All three tools connect to the same server on 127.0.0.1:9877.
• The working principles. Candidates as a numbered list, only the chosen ones applied, saving only when asked. That assumes you installed the rules file.

What differs

	Claude Code	Codex CLI	Gemini CLI
Register	claude mcp add --scope user cadxray -- uvx …	codex mcp add cadxray -- uvx …	gemini mcp add cadxray uvx …
Config file	(the command is enough)	~/.codex/config.toml	~/.gemini/settings.json
Rules file	CLAUDE.md (in the repository under that name)	AGENTS.md (save CLAUDE.md under this name)	GEMINI.md (same)
Check connection	/mcp	codex mcp list	/mcp
Screenshots	shown as images in the chat (verified)	depends on version	depends on version
Verification	the tool cadxray was developed and verified on	registration instructions in the README only	registration instructions in the README only

Screenshots are only for confirmation

Work proceeds fine without images. The AI judges by numbers — volume, degrees of freedom, boolean difference, safety factor — and you can look at the FreeCAD window yourself. Real verification was done with Claude Code. If you find Codex or Gemini behaving differently, please leave a note on GitHub Issues.

Things to watch for, whichever you use

• When Windows cannot find uvx: either you did not reopen the terminal, or a GUI app has a different PATH. Put the output of (Get-Command uvx).Source into command.
• The first run takes 10–30 seconds: that is the bridge downloading. If the tools do not appear, connect once more.
• If you changed the port, append --port 9878 to the registration command or to args.
• Run only one FreeCAD. Several AI tools can attach to the same FreeCAD at once, but do not let two of them edit the same document simultaneously.
• It works without the rules file, driven by the tool descriptions alone — but without the diagnostic order it may start looking in the wrong place. You are better off installing the file.

Which one to pick

If you already use one of them, use that. If not, Claude Code: screenshots appear in the chat, the rules file works under its own name, and the exercises on this site were verified against it.