freecad-addon-robust-mcp-server (spkane)
A FreeCAD MCP suite combining a bridge workbench with a standalone server, offering CAD tools, headless mode, STEP/STL export, and connection resilience.
What it does and how it connects
The FreeCAD Robust MCP Server connects AI assistants such as Claude and GPT to FreeCAD for AI-assisted development and debugging of 3D models, macros, and workbenches. It ships as two parts: a bridge workbench that runs inside FreeCAD and a standalone MCP server, installable by pip, from GitHub release assets, from source with uv, or as a Docker image, with a PyPI package and documentation site.
The server provides 150 plus tools organized into categories, covering primitives, PartDesign, booleans, and export and import, including export_step for STEP format. It supports full modeling in headless mode for automation and CI, with screenshots and colors available in GUI mode, and the README emphasizes connection resilience in the bridge between the client and FreeCAD.
The project is actively maintained, with workbench release v0.7.1 published on 2026-11-06, the same day as this verification; PR #211 records that release in the project's CAM compatibility inventory. The repo also links a companion macro project for 3D print multi-export.
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 bridge workbench plus standalone server with 150 plus tools.
- freecad-mcp (blwfish)
A FreeCAD MCP bridge built for daily use with 32 tools for modeling, CAM, and diagnostics, rather than a 150 plus tool suite with headless mode.
- freecad_mcp (bonninr)
A minimal socket-based MCP workbench with two core commands, rather than a full suite with a bridge workbench and a standalone server.
- freecad-mcp (contextform)
An MCP bridge for FreeCAD with a two-command installer and an AI Copilot workbench, rather than a bridge workbench plus standalone server.
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 repo activity is maintainer pull requests and bot commits.
- 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.