freecad-mcp (blwfish)
An MCP server that exposes FreeCAD modeling, CAM, and diagnostic operations to AI agents, packaged with an agent-debugging manual for troubleshooting CAD workflows.
What it does and how it connects
freecad-mcp is a bridge between an AI agent and FreeCAD, described by its author as a thinking partner for parametric design, CNC toolpath generation, and mesh work. The repo description states 32 tools. The agent handles the FreeCAD mechanics while the user brings design intent and domain judgment, and the two work through a design together, diagnose errors, iterate on existing parts, and check work before committing.
Its coverage spans modeling from requirements, diagnosing broken models by reading the FreeCAD Report View and inspecting sketch constraints, planning CNC toolpaths, building reusable macros from spreadsheets of dimensions, checking geometry errors and printability, working with meshes such as imported STL files, and exporting STEP and G-code for manufacturing. All tools except CAM are supported on FreeCAD 1.1.x, while CAM toolpath generation requires a current FreeCAD weekly development build.
The project is built for the author's personal daily use, designing parts and generating toolpaths to print and cut them, not as a demo. The README includes worked scenarios such as debugging a broken external reference and designing a parametric shingles generator, plus an agent-debugging manual for troubleshooting CAD workflows.
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 personal daily-use bridge with CAM and diagnostics.
- freecad-addon-robust-mcp-server (spkane)
A FreeCAD MCP suite with 150 plus tools, headless mode, and connection resilience, rather than a 32 tool personal-use bridge.
- freecad_mcp (bonninr)
A minimal socket-based MCP workbench with two core commands, rather than a full modeling, CAM, and diagnostic toolset.
- FreeCAD-MCP (ATOI-Ming)
A macro-centric FreeCAD MCP plugin with a GUI control panel and a client for running macros, rather than a general modeling bridge.
- 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 independent user voice found: recent issues are by the maintainer or dependency bots.
- 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.