Onshape MCP
Onshape MCP builds CAD models from chat requests: sketches, extrudes, assemblies with mates, and export to STEP or STL.
- 163 ★ on the repository
- Last commit
Extended access
Why this level
- The agent creates, changes and deletes objects in Onshape documents on behalf of the API key owner.
Install
- Works in
Manual install
git clone https://github.com/hedless/onshape-mcp.gitFirst installation step from the README. Then a virtual environment and `pip install -e .`.
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- The agent creates, changes and deletes objects in Onshape documents on behalf of the API key owner.
This is third-party code. Review the repository files before installing.
What it does
Onshape MCP is a Python server that drives Onshape through its REST API. The agent finds documents, draws sketches on the Front, Top and Right planes, extrudes and revolves them, adds fillets and chamfers, and builds linear and circular patterns. The README counts 45 tools. Assemblies get instance placement, positioning, four mate types (fastened, slider, revolute, cylindrical) and bounding-box interference checks. Dimensions can reference the document's variable table. A finished model exports to STL, STEP, PARASOLID, GLTF or OBJ.
Who it is for. Engineers and designers whose models live in Onshape and who would rather describe a part in words than place every dimension by hand.
Good fit when
- A housing or bracket has to be built from dimensions in a client thread.
- Two parts in an assembly overlap and the agent is asked to find the conflict.
- Part parameters sit in a variable table and change from chat.
- A finished model is exported to STEP for a subcontractor.
Not a fit when
- Dimensions are in millimetres and nobody converts them to inches, since the sketch tools take inches.
- The model lives in another CAD system such as SolidWorks or FreeCAD.
- The Onshape account owner does not issue API keys.
Example request
List my Onshape documents, create a Part Studio, draw a 4 by 2 inch rectangle on the Top plane and extrude it 0.5 inch.MCP
- Transport
- stdio
- Authentication
- API key
Environment variables
ONSHAPE_ACCESS_KEYrequired, secret- Access Key from the Onshape developer portal
ONSHAPE_SECRET_KEYrequired, secret- Secret Key from the Onshape developer portal
Limitations
You need an Onshape account with API access and a key pair, Access Key and Secret Key. The sketch tools take inches and degrees, so the agent converts metric sizes itself. Interference is found from bounding boxes; parts of complex shape can trigger false positives. The README installs the server from a cloned repository and expects an absolute path to the virtual environment's Python in the config. The agent creates, changes and deletes objects in your Onshape documents, so use a separate test document for the first runs.
How to disable. Remove the onshape block from `mcp.json` and restart Claude Code. Revoke the API keys in the Onshape developer portal.
FAQ
Where do I get the keys?
Create an API key in the Onshape developer portal and copy the Access Key and Secret Key. Pass them in `ONSHAPE_ACCESS_KEY` and `ONSHAPE_SECRET_KEY` or in a `.env` file.
How do I check the connection?
Restart Claude Code after editing `mcp.json` and ask for your Onshape documents. A returned list means the server works.
Which units do sketches use?
The sketch tools take inches and angles in degrees. Convert metric sizes before calling a tool.
Which export formats exist?
STL, STEP, PARASOLID, GLTF and OBJ, for Part Studios and for assemblies.
Is it safe to give the agent the keys?
The keys grant access to your Onshape documents and the agent may change and delete objects. Use a separate document for trials and revoke the key when it is not needed.
Discussion
No questions or reviews yet.
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Comparison with similar tools
Cards that share the main search query, and how they differ.
| Tool | Official | Authentication | Repository stars | Main difference |
|---|---|---|---|---|
| Onshape MCP (this card) | no | API key | 163 | |
| FreeCAD MCP | no | not required | 3,234 | drives desktop FreeCAD; Onshape MCP works with cloud Onshape through the REST API and access keys |
| Fusion 360 MCP | no | not required | 144 | connects an agent to Fusion 360; Onshape MCP adds assembly mates and Onshape variable tables |
README in short
The server installs from a clone into a virtual environment. Start it with `onshape-mcp` or `python -m onshape_mcp.server`; Claude Code connects it through a block in `mcp.json`.