freecad-mcp (neka-nat)
A FreeCAD MCP bridge that lets AI assistants like Claude Desktop create and edit objects, run FEM analysis, and take screenshots inside FreeCAD.
What it does and how it connects
FreeCAD MCP lets Claude Desktop and other MCP clients control FreeCAD: create and edit models, run Python scripts, inspect documents, and run FEM analyses. It has two components, an addon running inside FreeCAD and an MCP server launched by the client, connected over localhost by default.
Setup is a FreeCAD addon install plus a uvx launched server. The user copies the FreeCADMCP addon into the FreeCAD addon directory, restarts FreeCAD, selects the MCP Addon workbench, and starts the RPC server from the FreeCAD MCP toolbar. The client config then points at the uvx freecad-mcp command.
The README documents installation, configuration, tools, code execution, and demos, including a flange design demo, a toy car, modelling from a 2D drawing, and integrations with ADK and LangChain. The tools guide covers FEM analysis, screenshots, GUI execution, background jobs, and headless scripts.
What engineers report
Found while testing every tool end to end on a 100×10×10 mm steel cantilever (one end fixed, 100 N transverse load). I patched each one locally and verified the fixes; the patches are below.
2026-11-04Read the originalwhy not put everything into one (folder) freecad has a default python environment not?
2026-11-01Read the original
Alternatives
Compare side by side- freecad-mcp (blwfish)
A FreeCAD MCP bridge built for daily use with 32 tools for modeling, CAM, and diagnostics, rather than an addon plus server split with FEM analysis.
- freecad-addon-robust-mcp-server (spkane)
A FreeCAD MCP suite with 150 plus tools, headless mode, and connection resilience, rather than an addon plus server pair.
- freecad_mcp (bonninr)
A minimal socket-based MCP workbench with two core commands, rather than a full addon and server with FEM and screenshots.
- freecad-mcp (contextform)
An MCP bridge for FreeCAD with a two-command installer and an AI Copilot workbench, rather than an addon plus uvx server pair.
- MecAgent
A separate commercial desktop copilot that acts inside the open SolidWorks session, rather than an open source MCP server for FreeCAD.
Recurring errors it addresses
Error Index entries this tool is built to reduce or work around.
- A CAD agent bridge's screenshot tool refused any image over a 50KB socket frame, so every real model screenshot was dropped, and images that did fit arrived as base64 text inside JSON instead of real image blocks. The agent's only visual feedback channel was dead for production-scale models.Error Index
- When an agent fans out parallel create calls through the FreeCAD MCP bridge, the shared connection races: the first object is created even though its call reports failure, and the second object is silently never created with the status still showing healthy.Error Index
- A FreeCAD MCP bridge's autosave-before-call rewrote the active document on every tool call even with zero unsaved changes, stamping phantom diffs onto git-tracked CAD files. Agent activity pollutes version control with edits no human authored.Error Index
- A FreeCAD MCP bridge reported clean instance shutdowns as failures 100 percent of the time on Linux, because its liveness check polled immediately after signaling the process group. The agent was sent to retry or kill processes that were already gone.Error Index
- A FreeCAD MCP bridge silently ignored parameters the client materialized from JSON-Schema defaults, so box(size=20) produced a default 10mm shape. The agent believes it built the requested geometry while the model is something else entirely.Error Index
Sources
Not verified
- No GitHub releases exist, so latest release fields are null.
- Pricing: none stated on the repo.
Last verified November 6, 2026. Listings are informational. The evidence score measures public, verifiable evidence and is not an endorsement or a compatibility claim.