FreeCAD (local)
FreeCAD is open-source parametric CAD. MCPBundles reaches it on the user's machine through MCPBundles Desktop — the same pattern as ComfyUI or Obsidian. The user does not install a separate local MCP server; Desktop owns the localhost bridge into FreeCAD.
Runtime requirements
- FreeCAD installed and open on the user's machine while agents work.
- MCPBundles Desktop running on the same machine (forwards tool calls to localhost).
- Modeling runs on the user's CPU/GPU; heavy boolean ops can take minutes.
Document and object model
- Documents hold a scene graph. FreeCAD sanitises names (My Part → My_Part, duplicates get numeric suffixes). Always use document_name / object_name returned by create tools in follow-up calls — never assume the requested label survived unchanged.
- Objects are typed (Part::Box, Part::Cylinder, Part::Sphere, …). Primitives expose dimensional properties (Length, Width, Height, Radius, …).
- doc.recompute() runs after edits; create/edit/delete tools recompute automatically, but custom execute_code may need an explicit recompute.
Recommended workflow (3D print)
- Ping / status — confirm FreeCAD is reachable through Desktop before building geometry.
- Create document — capture the actual document_name from the response.
- Create primitives or generic objects — boxes/cylinders/spheres or Part:: types with property dicts.
- Inspect — list or get objects when names or dimensions are uncertain.
- Export STL or STEP to an absolute path on the user's disk (for example ~/Documents/exports/part.stl).
- Read exported file when the agent needs bytes or a spillover download link for slicing review.
Parts library
When available in the user's FreeCAD install, list the parts library and insert standard components (fasteners, bearings) by relative library path.
Screenshots
Optional isometric PNG captures help visual review. Some workbench views (TechDraw, Spreadsheet) cannot screenshot — the tool returns a clear null/error instead of failing silently.
Gotchas
- GUI thread: Modeling dispatches to FreeCAD's GUI thread. Very heavy OCCT booleans may time out — use async code execution and poll object state for long jobs.
- Desktop app: Expect the FreeCAD GUI application, not a headless freecadcmd-only workflow.
- Export paths: Use absolute paths on the user's machine. Optional allowed file roots on the connection restrict which directories Desktop may read.
- Name drift: Treat every create response's document_name / object_name as authoritative.
- No cloud fallback: If Desktop or FreeCAD is down, fix the local setup — do not substitute another CAD service.
