FreeCAD MCP

This repository is a FreeCAD MCP that allows you to control FreeCAD from Claude Desktop.

Demo

Design a flange

Design a toy car

Design a part from 2D drawing

Input 2D drawing

Demo

This is the conversation history. https://claude.ai/share/7b48fd60-68ba-46fb-bb21-2fbb17399b48

Install addon

FreeCAD Addon directory is

• Windows: %APPDATA%\FreeCAD\Mod\
• Mac:
  • FreeCAD 1.1: ~/Library/Application\ Support/FreeCAD/v1-1/Mod/
  • FreeCAD 1.0: ~/Library/Application\ Support/FreeCAD/v1-0/Mod/
• Linux:
  • Ubuntu: ~/.FreeCAD/Mod/ or ~/snap/freecad/common/Mod/ (if you install FreeCAD from snap)
  • Debian: ~/.local/share/FreeCAD/Mod
  • Arch / CachyOS (FreeCAD 1.1 from extra/freecad): ~/.local/share/FreeCAD/v1-1/Mod/
  • Flatpak: ~/.var/app/org.freecad.FreeCAD/data/FreeCAD/v1-1/Mod/

Please put addon/FreeCADMCP directory to the addon directory.

git clone https://github.com/neka-nat/freecad-mcp.git
cd freecad-mcp

# For Linux (Ubuntu/Debian)
mkdir -p ~/.FreeCAD/Mod/
cp -r addon/FreeCADMCP ~/.FreeCAD/Mod/

# For Linux (Arch/CachyOS, FreeCAD 1.1 from extra/freecad)
mkdir -p ~/.local/share/FreeCAD/v1-1/Mod/
cp -r addon/FreeCADMCP ~/.local/share/FreeCAD/v1-1/Mod/

# For Linux (Flatpak)
mkdir -p ~/.var/app/org.freecad.FreeCAD/data/FreeCAD/v1-1/Mod/
cp -r addon/FreeCADMCP ~/.var/app/org.freecad.FreeCAD/data/FreeCAD/v1-1/Mod/

# For macOS (FreeCAD 1.1)
mkdir -p ~/Library/Application\ Support/FreeCAD/v1-1/Mod/
cp -r addon/FreeCADMCP ~/Library/Application\ Support/FreeCAD/v1-1/Mod/

When you install addon, you need to restart FreeCAD. You can select "MCP Addon" from Workbench list and use it.

And you can start RPC server by "Start RPC Server" command in "FreeCAD MCP" toolbar.

Auto-Start RPC Server

By default, the RPC server must be started manually each time FreeCAD opens. To start it automatically:

1. Open the FreeCAD MCP menu (switch to the MCP Addon workbench first)
2. Check Auto-Start Server

The setting is saved to freecad_mcp_settings.json and persists across sessions. On the next FreeCAD launch, the RPC server will start automatically once the application finishes loading.

You can disable it at any time by unchecking Auto-Start Server in the same menu.

Setting up Claude Desktop

Pre-installation of the uvx is required.

And you need to edit Claude Desktop config file, claude_desktop_config.json.

For user.

{
  "mcpServers": {
    "freecad": {
      "command": "uvx",
      "args": [
        "freecad-mcp"
      ]
    }
  }
}

If you want to save token, you can set only_text_feedback to true and use only text feedback.

{
  "mcpServers": {
    "freecad": {
      "command": "uvx",
      "args": [
        "freecad-mcp",
        "--only-text-feedback"
      ]
    }
  }
}

Screenshots can also be controlled per tool call instead of globally: every tool that returns a screenshot accepts an optional include_screenshot parameter (pass false to get text-only feedback, e.g. for analytical scripts or intermediate steps) and an optional view_name parameter to orient the screenshot ("Isometric" by default, or "Front", "Top", "Right", etc.). The --only-text-feedback flag always wins: when it is set, no screenshots are returned regardless of include_screenshot.

For developer. First, you need clone this repository.

git clone https://github.com/neka-nat/freecad-mcp.git

{
  "mcpServers": {
    "freecad": {
      "command": "uv",
      "args": [
        "--directory",
        "/path/to/freecad-mcp/",
        "run",
        "freecad-mcp"
      ]
    }
  }
}

Remote Connections

By default the RPC server does not accept remote connections and listens on localhost. To control FreeCAD from another machine on your network:

1. Enable remote connections in FreeCAD

In the FreeCAD MCP toolbar:

1. Check Remote Connections — the RPC server will bind to 0.0.0.0 (all interfaces) on the next restart. For security reasons, it only accepts connections from the IP addresses or CIDR subnets specified in the Allowed IPs field. By default this is 127.0.0.1.

2. Click Configure Allowed IPs and enter a comma-separated list of IP addresses or CIDR subnets that are allowed to connect, e.g.:

   192.168.1.100, 10.0.0.0/24
   

   127.0.0.1 is always the default. Invalid entries are rejected with an error dialog. Restart the RPC server after changing these settings.

2. Point the MCP server at the remote host

Pass the --host flag with the IP address or hostname of the machine running FreeCAD:

{
  "mcpServers": {
    "freecad": {
      "command": "uvx",
      "args": [
        "freecad-mcp",
        "--host", "192.168.1.100"
      ]
    }
  }
}

The --host value is validated on startup — it must be a valid IPv4/IPv6 address or hostname.

Tools

• create_document: Create a new document in FreeCAD.
• create_object: Create a new object in FreeCAD.
• edit_object: Edit an object in FreeCAD.
• delete_object: Delete an object in FreeCAD.
• execute_code: Execute arbitrary Python code in FreeCAD.
• insert_part_from_library: Insert a part from the parts library.
• get_view: Get a screenshot of the active view.
• get_objects: Get all objects in a document.
• get_object: Get an object in a document.
• get_parts_list: Get the list of parts in the parts library.
• get_rpc_status: Report RPC and GUI-dispatch health without using the FreeCAD GUI thread.
• run_fem_analysis: Run the CalculiX solver on an existing Fem::FemAnalysis and return summary results (max von Mises stress, max displacement, node count, working directory). Auto-creates a SolverCcxTools if the analysis has none. See examples/cantilever_fem.py for an end-to-end usage example.

Tools that return a screenshot (create_object, edit_object, delete_object, execute_code, insert_part_from_library, get_objects, get_object, run_fem_analysis) accept optional include_screenshot (default true) and view_name (default "Isometric") parameters to suppress or reorient the returned image per call.

GUI dispatch timeouts

If a GUI-thread operation exceeds its timeout after it has started, the bridge returns GUI_DISPATCH_STUCK and rejects later GUI operations immediately. Use get_rpc_status to identify the operation that is still running. FreeCAD GUI work cannot be force-cancelled safely; if the status does not return to healthy after the operation finishes, restart FreeCAD.

After an execute_code exception on a FreeCAD development build, inspect any new FeaturePython object before mutating or deleting it. In particular, do not continue with an object whose required Proxy was never installed, as touching that broken object can wedge FreeCAD's GUI thread.

Contributors

Made with contrib.rocks.