If you have tried to get an AI agent to make a real, editable 3D part, you have probably hit the same wall: it writes an STL or a pile of OpenSCAD, and the moment you want to change one dimension you start over. A parametric CAD tool with a feature timeline fixes that, and SolidCraft is one that ships with its own MCP server.
tangency-labs/solidcraft is an open-source parametric 3D CAD application written in pure Rust. Per the README you sketch, constrain and build solids on a parametric feature timeline, change a dimension and watch the model rebuild, and run it on desktop, in the browser, or let AI agents model through the built-in MCP server. This post walks through the setup for Claude Code and what to expect.
The README calls it "early but usable for simple parts" and backs that with a number: 75 of 76 public reference parts match their analytic or FreeCAD-computed volume, area, centre of mass and bounding box. The one miss is a tracked bug.
The feature list is already broad:
.sc designs.
The important line for agent users is the last one in that list: the desktop app, browser app, headless CLI and MCP server all run the same commands. Whatever the agent does, you can open and edit by hand.
Pick the build for your machine from the README:
sudo snap install solidcraft
If you prefer to build from source with Rust:
cargo run --release -p solidcraft -- --sample # desktop app with a sample part
cargo run --release -p solidcraft-cli -- commands # the command registry
solidcraft-cli mcp is a Model Context Protocol server. One line registers it with Claude Code:
claude mcp add solidcraft -- solidcraft-cli mcp
Two modes are worth knowing. Run headless, the server keeps its own design session. Started with --connect, it drives the running desktop app so you can watch every feature appear on the timeline. For a first session, the connected mode is far easier to trust.
On older Windows installers the CLI is not on PATH. The README says to give the full path instead, which by default is C:\Program Files\SolidCraft\solidcraft-cli.exe.
The README's own demo is a good template for a prompt: a Raspberry Pi 4 case built from an empty design, with a sketch dimensioned from the board's parameters, extrude, fillet and shell, M2.5 standoffs patterned on the 58 by 49 mm hole rectangle, port cut-outs, vent slots and engraved text. Then the case height goes from 24 to 32 mm in Parameters and everything rebuilds.
So ask for parameters, not just a shape:
Create a box enclosure 90 x 60 mm with a height parameter of 30 mm,
2 mm walls (shell), 1 mm fillets on the outer edges, and four M3 standoffs
patterned on a 70 x 40 mm rectangle. Name every dimension as a parameter.
When it is done, change height in the Parameters panel yourself. If the model rebuilds cleanly, the agent built it the right way. Export STEP for a machinist or STL or 3MF for a printer.
A SolidCraft script is a JSON list of the same commands the UI runs. You can run one headless and write a file:
cargo run --release -p solidcraft-cli -- run examples/bracket.json --out bracket.step
This is handy once the agent has produced a part you like: keep the command list in the repo and regenerate the STEP in CI instead of trusting a binary file.
The builds we track on the SolidCraft page show where it fits:
If you want text-to-CAD as a skill set for agents rather than a full CAD app, text-to-cad generates 3D CAD models from text and runs related manufacturing and drawing workflows locally. For organic shapes, scenes and renders instead of engineering parts, MCP for Blender connects Blender to an LLM the same way.
Source repo: tangency-labs/solidcraft. License: MIT or Apache-2.0.
Want the setup commands for 50 AI repos people actually ship with? Get the free AI Repos That Actually Ship pack: https://dedupedai.com/ship-pack/?utm_source=devto&utm_medium=article&utm_campaign=shippack