OCP Viewer MCP Server

# OCP Viewer MCP Server [](https://badge.fury.io/py/ocp-viewer-mcp) [](https://opensource.org/licenses/MIT) An MCP (Model Context Protocol) server that captures screenshots from the [OCP CAD Viewer](https://github.com/bernhard-42/vscode-ocp-cad-viewer), allowing AI assistants like [Cursor](https://cursor.sh) to "see" your 3D CAD models. ## What it does When working with CAD tools like [CadQuery](https://github.com/CadQuery/cadquery) or [Build123d](https://github.com/gumyr/build123d), you can display models in the OCP CAD Viewer using `show()`. This MCP server lets you ask an AI assistant to capture what's currently displayed, enabling visual feedback and AI-assisted CAD development. **Example workflow:** 1. You're designing a part in a Jupyter notebook with CadQuery 2. You run `show(my_part)` to display it in the OCP viewer 3. You ask the AI: *"capture the current view - does this geometry look correct?"* 4. The AI captures a screenshot and can analyze the 3D model visually ## Installation ```bash pip install ocp-viewer-mcp ``` **Requirements:** - Python 3.10+ - [OCP CAD Viewer](https://marketplace.visualstudio.com/items?itemName=bernhard-42.ocp-cad-viewer) VS Code/Cursor extension - [ocp-vscode](https://pypi.org/project/ocp-vscode/) Python package (for `show()` function) ## Configuration ### Cursor Add to your `~/.cursor/mcp.json`: ```json { "mcpServers": { "ocp-viewer": { "command": "python", "args": ["-m", "ocp_viewer_mcp.server"] } } } ``` If you're using a virtual environment (recommended), specify the full Python path: ```json { "mcpServers": { "ocp-viewer": { "command": "/path/to/your/venv/bin/python", "args": ["-m", "ocp_viewer_mcp.server"] } } } ``` ### Claude Desktop Add to your Claude Desktop config (`~/Library/Application Support/Claude/claude_desktop_config.json` on macOS): ```json { "mcpServers": { "ocp-viewer": { "command": "python", "args": ["-m", "ocp_viewer_mcp.server"] } } } ``` ## Usage 1. **Open** your CadQuery/Build123d project in Cursor or VS Code 2. **Start** the OCP CAD Viewer (Cmd+Shift+P → "OCP CAD Viewer: Open Viewer") 3. **Display** a model using `show(your_model)` in a notebook or script 4. **Ask** the AI to capture the view: - "Capture the current OCP view" - "Show me what the model looks like" - "Take a screenshot of the CAD viewer" ## Tool Reference ### `capture_ocp_screenshot` Captures a screenshot of the OCP CAD Viewer. | Parameter | Type | Default | Description | |-----------|------|---------|-------------| | `port` | integer | 3939 | The port where OCP viewer is running | | `wait_ms` | integer | 1000 | Milliseconds to wait for rendering | **Returns:** A PNG screenshot as a base64-encoded image. ## Troubleshooting ### "Could not connect to OCP viewer" - Make sure the OCP CAD Viewer is open in VS Code/Cursor - Check that the viewer backend is running (look for "Viewer backend started" in terminal) - Verify the port (default is 3939) ### "ocp_vscode not installed" The MCP server needs `ocp-vscode` installed in the same Python environment: ```bash pip install ocp-vscode ``` ### Screenshot not capturing - Make sure a model is displayed (run `show(something)` first) - Try increasing `wait_ms` if the model is complex ## Development ```bash # Clone the repo git clone https://github.com/dmilad/ocp-viewer-mcp.git cd ocp-viewer-mcp # Install with Poetry poetry install # Run locally poetry run python -m ocp_viewer_mcp.server ``` ## Contributing Contributions are welcome! Please open an issue first to discuss what you'd like to change. ## License [MIT](LICENSE) ## Related Projects - [OCP CAD Viewer](https://github.com/bernhard-42/vscode-ocp-cad-viewer) - The VS Code extension this MCP server integrates with - [CadQuery](https://github.com/CadQuery/cadquery) - Python parametric CAD scripting - [Build123d](https://github.com/gumyr/build123d) - Python CAD scripting with a builder pattern - [MCP](https://modelcontextprotocol.io/) - Model Context Protocol specification