kernelcad — Claude Code MCP server: CAD from source
Turns a plain-language part description into editable .kcad.ts source, checks the model, and prepares manufacturing artifacts.
claude mcp add --transport http kernelcad https://mcp.kernelcad.com/mcpWhat kernelcad does
kernelCAD sits above the OpenCASCADE kernel and is built for an agent to drive. The loop: a design brief becomes .kcad.ts source, that source evaluates into a model, the model goes through deterministic validation, gets revised if needed, and leaves as an export package. Feature history, diagnostics and variants live in the source text, so an agent can read and edit the model as code.
The server is hosted at https://mcp.kernelcad.com/mcp. Nothing runs on your machine and OpenCASCADE does not need to be installed. Anonymous use works; your client will prompt for OAuth sign-in when you want account features. The same account covers ChatGPT, Claude and the coding agents, and a saved model opens at the same /p/<slug> share link everywhere.
Checks go past the render. Assemblies such as the planetary stage or the bevel drive carry revolute mates and gear ratios derived from tooth counts, and kernelcad validate --include-interference looks for overlapping teeth. For printing there is a gate: kernelcad dfm checks wall thickness and unsupported overhangs. Prefer a local process? The second install command starts the server through npx -y kernelcad.
What it helps with
- get editable part source instead of a binary file
- check an assembly for overlapping teeth before printing
- run FDM print checks on a model
- build variants of one part from parameters
- hand a model to a human reviewer with its history
Example prompts for the agent
- Build a hollow hex vase 150 mm tall with a 2 mm wall and save it as
.kcad.ts - Check the bevel gear pair for tooth interference with
evaluate_script - Export the part to STEP and tell me what the print checks say
How to install kernelcad
1Platform CLI: remote server
claude mcp add --transport http kernelcad https://mcp.kernelcad.com/mcp2Platform CLI
claude mcp add kernelcad -- npx -y kernelcad1Platform CLI: remote server
codex mcp add kernelcad --url https://mcp.kernelcad.com/mcp2Platform CLI
codex mcp add kernelcad -- npx -y kernelcadConfig file
{
"mcpServers": {
"kernelcad": {
"url": "https://mcp.kernelcad.com/mcp"
}
}
}{
"mcpServers": {
"kernelcad": {
"command": "npx",
"args": [
"-y",
"kernelcad"
]
}
}
}Config file
{
"servers": {
"kernelcad": {
"type": "http",
"url": "https://mcp.kernelcad.com/mcp"
}
}
}{
"servers": {
"kernelcad": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"kernelcad"
]
}
}
}1Platform CLI: remote server
gemini mcp add -t http kernelcad https://mcp.kernelcad.com/mcp2Platform CLI
gemini mcp add kernelcad npx -y kernelcadStep 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 kernelcad
How do I install kernelcad in Claude Code?
Run claude mcp add --transport http kernelcad https://mcp.kernelcad.com/mcp. For a local process instead, run claude mcp add kernelcad -- npx -y kernelcad. Restart the app afterwards.
What does kernelcad do?
It runs the design loop from a text brief to .kcad.ts source, then to an evaluated model, validation and export. It is the workflow layer above the OpenCASCADE kernel.
Do I need OpenCASCADE installed locally?
No. The hosted server at https://mcp.kernelcad.com/mcp needs no local install, and anonymous use is available without signing in.
