SolidCraft is a parametric CAD app a coding agent can drive over MCP: Reveneau

Why it mattersA coding agent can now sketch, extrude, pattern and export a parametric 3D model inside a visible timeline rather than describing one in words, so somebody who did not want to learn Fusion 360 can ask an agent to make a bracket and inspect the result.

A new open-source CAD app lets a coding agent draw a parametric 3D model instead of generating a one-shot mesh. SolidCraft, released by GitHub user bherbruck under Apache-2.0, is a parametric 3D CAD application written in pure Rust, with a desktop app for every platform, a browser build, a headless command-line interface and an MCP server. The repository was created on 7 October and reached 1,840 stars by 14 October.

The pitch, in the README's own words, is that SolidCraft covers "sketching with constraints, parametric features and assemblies", in the shape of Autodesk's Fusion 360. An agent that speaks the Model Context Protocol can sketch, extrude, pattern, measure, screenshot and export without a person touching the mouse.

What the app does

The sketcher supports lines, rectangles, circles, arcs, polygons, slots, ellipses, splines and text, with construction geometry, trimming and fillets. The constraint solver handles coincident, tangent, parallel, perpendicular and dimensional constraints. The feature timeline includes extrude, revolve, sweep, loft, fillet, chamfer, shell, draft, hole, thread, pattern, mirror, split, combine and move. Assemblies carry nested components, joints, motion studies, contact sets, interference and material-aware mass properties. Sheet metal supports fold and unfold.

Files move in and out through STEP (AP203, AP214 and AP242), IGES 5.3, STL, OBJ and 3MF, plus URDF export for robotics work.

The MCP server

The MCP server exposes a short tool set that a coding agent calls directly: list_commands, execute, batch, inspect_design, measure, body_topology, set_parameter, screenshot, export, undo, redo, new_design, open and save. The server runs headless on its own or connects to the desktop app for visual review.

What the author measured

The README says 75 of 76 public reference parts match the analytic or FreeCAD-computed volume, surface area, centre of mass and bounding box. The single failure is tracked as a known bug. The project is marked "early but usable for simple parts".

How a reader uses it

A coding agent such as Claude Code, Codex or Cursor opens the headless server, runs a batch of commands to lay out a sketch, applies constraints, extrudes it, patterns the holes, measures the bounding box, saves a screenshot and exports a STEP file for a shop or a print-ready STL for a printer. A person looks at the screenshot the agent returned, says what to change, and the agent updates one dimension in the timeline rather than rebuilding the whole part. The desktop app is published for Windows, macOS and Linux, and the browser version runs the same code at bherbruck.github.io/solidcraft/app.

Reveneau's take, for a team that makes hardware or print-ready parts: a parametric file is the shape of a thing a person edits, and a mesh is throwaway. An agent driving a Fusion 360 shape is useful even on simple parts, because the second revision reads the timeline and changes one dimension. A one-shot mesh does not. The limit is the author's own: this is early, and the single matching failure is a reminder that the measurements can still be wrong on a part that looks right.

Source

bherbruck/solidcraft on GitHub.

This item was written by an AI system from the linked source. Reveneau is responsible for what it publishes.