Grasshopper 3D MCP server

GH_mcp_server is a powerful tool that enables interaction with Rhino and Grasshopper through Large Language Models (LLMs). It allows you to analyze .3dm files, perform 3D modeling tasks, and automatically generate GHPython code in Grasshopper based on natural language instructions.

Requirements

• Rhino 7 or 8
• RhinoPython: https://github.com/jingcheng-chen/RhinoPythonForVscode/tree/master
• UV package manager
• Claude Desktop

Installation

Set Up Prerequisites

First, install the UV package manager:

For MacOS and Linux:

curl -LsSf https://astral.sh/uv/install.sh | sh

For Windows:

powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"

Install GH_mcp_server

1. Clone the repository:

git clone [email protected]:veoery/GH_mcp_server.git
cd GH_mcp_server

2. Set up the environment:

For macOS/Linux:

uv venv
source .venv/bin/activate
uv pip install -e .

For Windows:

uv venv
.venv\Scripts\activate
uv pip install -e .

Note: Make sure the virtual environment is activated before running the project.

Configure Claude Desktop

1. In Claude Desktop, navigate to Settings → Developer
2. Click "Edit Config" to open the claude_desktop_config.json file
3. Add the following configuration to the JSON file:

{
  "mcpServers": {
    "grasshopper": {
      "command": "path_to_GH_mcp_server/.venv/bin/python",
      "args": [
        "path_to_GH_mcp_server/run_server.py"
      ]
    }
  }
}

4. Replace path_to_GH_mcp_server with the actual path to your GH_mcp_server installation
5. Restart Claude Desktop
6. If configuration is successful, you should see a hammer icon. Click it to check all attached MCP tools.

Usage

Basic Operation

1. Start Rhino
2. Type the command CodeListener in Rhino. You should see the message "VS Code Listener Started..."
3. Open Claude Desktop and interact with GH_mcp_server using natural language prompts

Example Commands

You can use prompts like these to interact with the tool:

Read the file "D:\test01.3dm" first and analyse the objects in this file.

Write GHPython to create a tower referring to zaha and write the ghpython code to "D:\zaha01.py"

The file examples\zaha01.gh provides a reference for interacting with Grasshopper through this tool.

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "grasshopper" '{"command":"path_to_GH_mcp_server/.venv/bin/python","args":["path_to_GH_mcp_server/run_server.py"]}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "grasshopper": {
            "command": "path_to_GH_mcp_server/.venv/bin/python",
            "args": [
                "path_to_GH_mcp_server/run_server.py"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "grasshopper": {
            "command": "path_to_GH_mcp_server/.venv/bin/python",
            "args": [
                "path_to_GH_mcp_server/run_server.py"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect