Hmmm good question, but what is the cad? Like you can ask anyone to just write openscad files directly. It gets more tricky for stuff like fusion and I don't know much about there.
Free or service? There is a lot with the advent of physical AI. I can help with that if you want. Drop me a message. I've built some things that are not public to make custom parts for robots. can share my research (not the solution due to NDA, sorry)
I had some success with FreeCAD and a local MCP-server package connected to Claude Code locally.