Back to Browse
Free
Server data from the Official MCP Registry
Inspect STEP CAD geometry, topology, mass properties, and PMI via MCP.
About
Inspect STEP CAD geometry, topology, mass properties, and PMI via MCP.
Security Report
10.0
Low Risk10.0Low RiskValid MCP server (1 strong, 1 medium validity signals). No known CVEs in dependencies. Package registry verified. Imported from the Official MCP Registry.
8 files analyzed · 1 issue found
Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.
Permissions Required
This plugin requests these system permissions. Most are normal for its category.
How to Install
Add this to your MCP configuration file:
{
"mcpServers": {
"io-github-mattmohandiss-cad-mcp-server": {
"args": [
"-y",
"cad-mcp-server"
],
"command": "npx"
}
}
}Documentation
View on GitHubFrom the project's GitHub README.
CAD MCP Server
Read-only CAD inspection for LLMs, zero install. Bundles a WebAssembly Open CASCADE 8.0 kernel so AI assistants can read, measure, and compare STEP files locally. Returns deterministic geometry facts — the LLM interprets engineering meaning.
Quick Start
npx -y cad-mcp-server
Add to your MCP client config (Claude Desktop, OpenCode, Cursor, etc.):
{
"mcpServers": {
"cad": {
"command": "npx",
"args": ["-y", "cad-mcp-server"]
}
}
}
Point the AI at any STEP or STP file on your local filesystem.
Use Cases
| Who | What they ask |
|---|---|
| Mechanical lead | "Review this STEP file like a mechanical lead before release. What are the top design or manufacturing risks?" |
| Manufacturing engineer | "Build a first-pass CNC plan: likely setups, drilling directions, and cost-driving features." |
| QC engineer | "Create an inspection plan from the STEP file. What should we measure? What's missing?" |
| Procurement / sourcing | "Prepare an RFQ summary: part count, envelope, complexity drivers, and questions the supplier will ask." |
| Design engineer (revision) | "Compare Rev A and Rev B as an ECO review. What changed? What should be rechecked?" |
| Hobbyist / maker | "Can these parts fit on a 200 x 200 x 300 mm printer? What needs splitting or reorientation?" |
MCP Tools (v0.2)
| Tool | Purpose |
|---|---|
inspect_step | First-pass overview: dimensions, volume, topology, principal axes, OBB, watertight check, PMI hints. Use this first. |
query_step | Declarative query: filter/sort/group faces, edges, bodies, vertices, PMI, colors, layers, materials, assembly. Measure distances, fire ray tests, compute sections, compute curvature. Aggregate stats. One call replaces 5+ primitive round-trips. |
diff_step | Compare two STEP files: metric deltas, topology changes, body-level changes, XDE-level changes. |
transact_step | Multi-step pipeline when a single query isn't enough: "for each hole, ray-test in +Z, then keep ones that didn't come out the other side." |
Design principle: Deterministic geometry only. No interpretation, no heuristics. The server measures; the LLM decides.
The seven primitives from the v0.1 surface (face search, edge search, entity lookup, PMI query, ray test, distance, coaxial grouping) are now expressible as query_step calls — for example, find_coaxial_cylinders becomes {entities: "faces", filter: {surface_type: "cylinder"}, group_by: ["axis"]}. See docs/EXAMPLE_PROMPTS.md for prompt patterns that work with this surface.
How It Works
STEP files are parsed locally by a stripped Open CASCADE Technology (OCCT 8.0) kernel compiled to WebAssembly. No data leaves your machine. No Docker, no cloud API, no CAD license.
Why CAD MCP Server?
- Zero install. One
npxcommand, no native CAD software, no licenses, no Docker, no cloud API. - Read-only. No geometry creation or modification.
- Local-first. STEP files never leave your filesystem.
- WASM performance. OCCT runs at near-native speed in a bundled WebAssembly kernel.
- LLM-native. Structured JSON output designed for AI consumption. Every tool has defaults, enums, pagination, and descriptions written for LLM reasoning.
- OCCT-native. Every computation uses OCCT built-in classes — no custom math where OCCT already provides it.
What It Is Not
- Not a CAD editor — no geometry creation or modification.
- Not a CAM system — no toolpath generation.
- Not a manufacturability certifier — it provides evidence, not conclusions.
- Not an AP242 PMI engine — PMI hints are lightweight and heuristic-based.
- Not a feature-tree recovery tool — STEP is a boundary-representation format.
Good AI answers separate measured facts, assumptions, and engineering recommendations.
Requirements
- Node.js 22 or newer
- Local access to STEP/STP files
No Docker, Open CASCADE install, or native CAD application required.
Distribution
The npm package is minimal: compiled JS, bundled occt-wasm WASM kernel, and TypeScript declarations.
Contributing
See CONTRIBUTING.md for setup, testing, and PR guidelines.
License
MIT. The bundled occt-wasm backend uses Open CASCADE Technology (LGPL-2.1). See THIRD_PARTY_NOTICES.md.
Support
If CAD MCP Server saves you time, consider sponsoring development.
Reviews
No reviews yet
Be the first to review this server!
More Developer Tools MCP Servers
Fetch
Freeby Modelcontextprotocol · Developer Tools
Web content fetching and conversion for efficient LLM usage
80.0K
Stars
5
Installs
5.3
Security
No ratings yet
Local
Git
Freeby Modelcontextprotocol · Developer Tools
Read, search, and manipulate Git repositories programmatically
80.0K
Stars
6
Installs
6.5
Security
No ratings yet
Local
Toleno
Freeby Toleno · Developer Tools
Toleno Network MCP Server — Manage your Toleno mining account with Claude AI using natural language.
137
Stars
531
Installs
8.0
Security
4.8
Local