SolidWorks MCP

MCP server that drives SolidWorks on Windows from Cursor (or another MCP client). Open and edit parts and assemblies, create geometry, mates, measure, rebuild, export, and more — without writing macros.

[!NOTE] Heavy WIP. This project is under active development. APIs, tools, and behavior will change. Expect rough edges, missing coverage, and breaking updates.

Needs: Windows · licensed SolidWorks · Cursor (or another MCP client) · Node.js 20+ · .NET 8 SDK
SolidWorks should be open (or launchable) on the same machine.

Workflow

1. Have SolidWorks running (open a document, or start from a blank session).
2. In Cursor, ask for the change you want — edit what’s open, or build a new part from scratch.
3. The assistant drives SolidWorks through this server.
4. Check the model, then confirm before it saves.

Examples:

• “List the mates on this assembly and tell me which ones are failing.”
• “Measure the distance between these two faces.”
• “Add a coincident mate between the flange face and the bracket face.”
• “Export a PNG of the current view so I can check the pose.”
• “Extrude a cube, then cut cylinders all the way through on each face.”
• “Save a checkpoint before we change anything.”

Destructive tools require confirm: true. Don’t save until you’ve said the model looks right.

Setup

On the Windows machine that runs SolidWorks:

1. Install Node and .NET

Node.js 20+ and the .NET 8 SDK.

2. Clone and build

git clone https://github.com/jaylamping/solidworks-mcp.git
cd solidworks-mcp
npm install
npm run build

3. Check SolidWorks

Start SolidWorks, then:

npm run worker:status

You should see a live COM connection (and the open document if any).

4. Connect Cursor

Point MCP at your clone (path placeholders → your real folder):

{
  "mcpServers": {
    "solidworks": {
      "command": "node",
      "args": [
        "C:/path/to/solidworks-mcp/node_modules/tsx/dist/cli.mjs",
        "C:/path/to/solidworks-mcp/src/index.ts"
      ],
      "env": {
        "SOLIDWORKS_MCP_TOOL_TIER": "extended",
        "SOLIDWORKS_MCP_ALLOWED_ROOTS": "C:/cad;D:/projects;C:/path/to/solidworks-mcp/.demo",
        "SOLIDWORKS_MCP_PERSISTENT_WORKER": "1"
      }
    }
  }
}

Reload MCP after saving. Call SolidWorks tools one at a time — COM is single-threaded.

Try the demo

With SolidWorks open and MCP connected, ask:

Extrude a cube, then cut cylinders all the way through on each face.

Or from the repo: npm run demo:build-part.

Tools

100+ tools across documents, assemblies, mates, modeling, measure/inspect, selection, URDF helpers, and low-level API invoke. Search with solidworks_search_tools, or see docs/api/.

Safety

• Mutating tools often auto-checkpoint under .checkpoints/ next to the document.
• Confirm the model (or a PNG) before a hard save.
• Assembly lock-in uses confirm_and_save (rebuild → mate health → save → reopen → pose check).
• Paths outside SOLIDWORKS_MCP_ALLOWED_ROOTS are rejected.

See Troubleshooting.

---

For developers

Cursor (or other MCP client)
  → Node (TypeScript MCP server)
  → SolidWorksComWorker (.NET 8, STA)
  → SolidWorks COM

Tool metadata: src/tool-spec/catalog.ts. Refresh with npm run generate:tools — don’t hand-edit generated allowlists. Persistent worker: SOLIDWORKS_MCP_PERSISTENT_WORKER=1 or SOLIDWORKS_MCP_WORKER_MODE=session.

npm run typecheck
npm run build
npm run generate:tools -- --check
npm run check:safety
npm run check:schemas
npm run validate:tools
npm run demo:build-part

demo:record-video regenerates docs/assets/ (needs SolidWorks + Edge + ffmpeg).

• Troubleshooting
• Error catalog
• CAD automation notes
• COM invoke ABI
• API reference corpus

License

MIT — see LICENSE.

SolidWorks® is a trademark of Dassault Systèmes. This project is not affiliated with or endorsed by Dassault Systèmes.