OwlCAD
Parametric 3D CAD for AI agents: build print-ready parts, check them, export STL, 3MF or STEP.
What can you do with OwlCAD?
- Build parts from primitives and booleans, built-in generators (gears, threads, Gridfinity
- Check them: watertight build, size and volume, overhangs, thinnest wall, collisions between
- Export STL, 3MF or OBJ for a slicer, STEP for other CAD tools, or a 2D drawing.
- List, read, edit, organize, share and delete your saved OwlCAD projects.
Install
Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).
claude mcp add --transport http owlcad 'https://mcp.owlcad.com'
{
"mcpServers": {
"owlcad": {
"type": "http",
"url": "https://mcp.owlcad.com"
}
}
}
Documentation
From the project's README on GitHub, refreshed weekly. Links open on GitHub.
Contents
OwlCAD
Parametric 3D CAD for 3D printing, for your AI assistant. This plugin connects Claude, GitHub Copilot in VS Code, Cursor or Gemini CLI to OwlCAD's hosted MCP server, so the assistant can build millimeter-dimensioned parts, check that they will print, and export STL, 3MF or STEP. Everything it makes is a normal OwlCAD project: a tree of named, dimensioned parts you can open in the browser editor at owlcad.com and change afterwards.
What it can do
- Build parts from primitives and booleans, built-in generators (gears, threads, Gridfinity bins and baseplates) and a library of datasheet-dimensioned parts.
- Check them: watertight build, size and volume, overhangs, thinnest wall, collisions between parts, and whether a part fits a given printer's bed. It can also cut an oversized part into printable pieces.
- Export STL, 3MF or OBJ for a slicer, STEP for other CAD tools, or a 2D drawing.
- List, read, edit, organize, share and delete your saved OwlCAD projects.
29 tools in all. The full list, with what each one does, is at owlcad.com/mcp-server.
Requirements
An OwlCAD account on the Pro plan. The first time the assistant uses OwlCAD, a browser opens so you can sign in and approve what it may do. You can revoke the connection at any time from Account settings on owlcad.com.
What it runs, sends and fetches
This plugin contains configuration only. It runs nothing on your machine. It points your
assistant at https://mcp.owlcad.com/, OwlCAD's hosted server. Each tool call sends that server
the model or project the assistant is working on, and the server reads and writes projects in
your OwlCAD account. How that data is handled is described in the
privacy policy.
Install
The server is https://mcp.owlcad.com/ (Streamable HTTP). It signs you in with OAuth, so there is
no API key to copy.
- Claude (web, desktop): open OwlCAD in Claude's directory
and select Connect. Or add it by URL: Settings → Connectors → Add custom connector, and paste
https://mcp.owlcad.com/. - GitHub Copilot in VS Code: run MCP: Add Server from the Command Palette, choose HTTP and
enter
https://mcp.owlcad.com/, or add it to.vscode/mcp.json, then sign in when VS Code asks:{ "servers": { "owlcad": { "type": "http", "url": "https://mcp.owlcad.com/" } } } - Claude Code:
claude mcp add --transport http owlcad https://mcp.owlcad.com/ - Cursor: add the server to
~/.cursor/mcp.json(or a project's.cursor/mcp.json), then sign in when Cursor asks:{ "mcpServers": { "owlcad": { "url": "https://mcp.owlcad.com/" } } } - Gemini CLI:
gemini extensions install https://github.com/Spare-Matter/owlcad-plugin
Other MCP clients that speak Streamable HTTP work the same way: point them at the URL and sign in.
Using it
Ask in plain language. For example:
- "Design a 60 mm wall hook with two screw holes and check that it prints."
- "Make a 2 by 3 Gridfinity bin, 6 units tall, and save it to OwlCAD."
- "Make a 20-tooth and a 40-tooth spur gear that mesh, check they don't collide, and export a STEP."
- "Export my latest OwlCAD project as a 3MF."
The assistant builds the model with OwlCAD's tools, checks it, and gives you a file or a link that opens the project in the editor, where every dimension can still be changed. Units are millimeters and Z points up.
Support
owlcad.com/contact · contact@owlcad.com
License
The files in this repository (configuration and documentation) are MIT-licensed; see LICENSE. The OwlCAD service they connect to is proprietary.
Frequently asked questions
What is OwlCAD?
Parametric 3D CAD for AI agents: build print-ready parts, check them, export STL, 3MF or STEP.
How do I install OwlCAD?
It runs as a remote server. In Claude Code: claude mcp add --transport http owlcad 'https://mcp.owlcad.com'. For other clients, paste the JSON configuration from this page into their MCP settings.
Does OwlCAD need an API key?
Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.
Is OwlCAD open source?
Yes. Its code is on GitHub under the MIT license.
Who maintains OwlCAD?
It is published by Spare-Matter. AI.tn lists it but does not maintain or endorse it.
From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.