freecad_mcp (bonninr)
A minimal socket-based MCP workbench for FreeCAD with two core commands: fetching scene information and running arbitrary Python scripts.
What it does and how it connects
FreeCAD MCP from bonninr is a minimal server-client bridge for FreeCAD that runs over a socket on localhost port 9876. It exposes two core commands: get_scene_info, which retrieves document properties, object details, sketch data, and view information, and run_script, which executes arbitrary Python code inside the FreeCAD context.
Because run_script runs any Python the client sends, the agent can create objects, modify the document, and automate tasks through the FreeCAD Python API, using the scene information as its readback. Configuration is a JSON MCP server entry pointing a Python executable at the freecad_bridge.py script, with per-OS paths documented for Windows, Linux, and macOS.
The README states the scope plainly: two commands, no tool catalog, no FEM, no CAM, and no GUI panel. It is the smallest of the FreeCAD MCP bridges in this batch, and its last push was March 2025.
What engineers report
I am running a current release of macOS and FreeCAD and found that I needed to install this in `~/Library/Application Support/FreeCAD/Mod` instead of in `~/Library/Preferences/FreeCAD/Mod` as listed in the README.
2025-06-04Read the original
Alternatives
Compare side by side- freecad-mcp (neka-nat)
The most widely used FreeCAD MCP server, with an addon plus server split and FEM analysis, rather than a minimal two-command socket workbench.
- freecad-mcp (blwfish)
A FreeCAD MCP bridge built for daily use with 32 tools for modeling, CAM, and diagnostics, rather than a minimal socket bridge.
- freecad-addon-robust-mcp-server (spkane)
A FreeCAD MCP suite with 150 plus tools, headless mode, and connection resilience, rather than a two-command socket server.
- freecad-mcp (contextform)
An MCP bridge for FreeCAD with a two-command installer and an AI Copilot workbench, rather than a socket-based workbench with two commands.
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.
- Activity: last push March 2025, so the project looks quiet; no newer release was found.
Last verified November 6, 2026. Listings are informational. The evidence score measures public, verifiable evidence and is not an endorsement or a compatibility claim.