Sketches, extrudes, revolves, booleans, fillets, chamfers, patterns, and first-class Variable Studios.
Build editable geometry and change named dimensions without starting again.
Cloud CAD MCP · Open source
Build, inspect, and refine Onshape with AI.
Ultron connects MCP-capable coding agents—including Codex and Claude Code—to real Onshape documents, combining parametric modelling with structured results, multi-view rendering, and a verify-after-every-change workflow.
≈60 tools
MIT licence
Cloud execution
ISO
A tighter CAD loop
Every modelling step should prove what changed.
- 01
Describe
Start from a written brief, dimensions, or a reference image.
- 02
Build
Create sketches and parametric features in the real Onshape document.
- 03
Read the truth
Structured mutation results expose changes, warnings, and regeneration failures.
- 04
See and correct
Render multiple views, compare geometry, and refine the next operation.
Roughly 60 tools
More than a primitive-by-primitive builder.
Multi-view rendering
Return front, top, right, and isometric views so the AI can inspect its work.
Image comparison
Load a drawing or photo, crop into features, and compare it with the current model.
Mates and interference
Place instances, create supported mates, align components, and check bounding boxes.
FeatureScript
Use custom features when the normal modelling surface is not expressive enough.
Measure and export
Inspect entities and mass properties, then export common CAD and mesh formats.
Geometric diffs and hints
See bounding-box, part-count, and mass changes with recovery hints for known failures.
Before you connect
Four pieces, one cloud workflow.
Ultron uses your Onshape account and API credentials to work with documents you choose. Credentials should stay in the operating-system keychain and never appear in a public issue.
Open the complete setup guide →- 1Onshape account
Access to the documents you want to use.
- 2API key and secret
A developer-portal key pair with appropriate access.
- 3Agentic coding tool
Codex, Claude Code, or another MCP-capable client.
- 4uv
The Python project and MCP server runtime.
Support and development
Share the failure—not your secret key.
For a useful report, include the failing tool, compact response, expected result, and a safe document or minimal reproduction. Remove API credentials and private document details first.