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/

Please put addon/FreeCADMCP directory to the addon directory.

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

# For Linux (Ubuntu/Debian)
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 macOS (FreeCAD 1.1)
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.

jsonCopy code
{
  "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.

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

For developer. First, you need clone this repository.

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

jsonCopy code
{
  "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.:

   Copy code
   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:

jsonCopy code
{
  "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.
• 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.

Contributors

Made with contrib.rocks.