ClassCAD — Claude Code MCP server: what it does, how to install
Runs the ClassCAD engine locally to build 3D parts and assemblies. Perfect for scripting CAD models, inspecting trees, and collaborating in real time.
claude mcp add classcad -- npx -y @classcad/mcpWhat ClassCAD does
The server runs the ClassCAD core via WebAssembly inside a local worker thread. No separate CAD server is needed. It allows coding agents to construct parametric components, inspect model trees, render snapshots, and export files to STEP, STL, or OFB. A background daemon coordinates connections on 127.0.0.1:9097. Through port 127.0.0.1:9098, the Buerligons CAD viewer links into the session so you can rotate and edit models while the agent writes code.
Setup requires Node.js 20+ and a free classcad.ch account. The server downloads roughly 16 MB of compiled assets on its first launch. Without that initial network access, initialization fails. Once cached, the engine works entirely offline. On native Windows, hosts cannot execute npx directly, requiring a cmd /c wrapper.
What it helps with
- generate mechanical components and assemblies using CAD scripts
- inspect model hierarchy trees and capture rendered snapshots
- export or import geometry using STEP, STL, and OFB files
- link the active modeling session directly to the Buerligons web viewer
Example prompts for the agent
- Construct a mounting bracket with four counterbored holes and save it as STEP
- Inspect the part tree for this assembly and export a snapshot image
- Open the current model in the Buerligons viewer so I can review it
How to install ClassCAD
Platform CLI
claude mcp add classcad -- npx -y @classcad/mcpPlatform CLI
codex mcp add mcp -- npx -y @classcad/mcpConfig file
{
"mcpServers": {
"mcp": {
"command": "npx",
"args": [
"-y",
"@classcad/mcp"
]
}
}
}Config file
{
"servers": {
"mcp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@classcad/mcp"
]
}
}
}Platform CLI
gemini mcp add mcp npx -y @classcad/mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about ClassCAD
How to install ClassCAD in Claude Code?
Run claude mcp add classcad -- npx -y @classcad/mcp in your terminal. Ensure that Node.js 20 or newer is present on your system.
What does ClassCAD do?
It exposes a local WebAssembly CAD engine to MCP hosts. The agent uses it to script solid models, manipulate part assemblies, and generate geometry files.
Does ClassCAD require an active internet connection?
Internet access is only needed during initial setup to download roughly 16 MB of engine files and authenticate. Subsequent operations run locally on your hardware.
