Polykrom is open-source parametric CAD in pure Rust. Model a part, check the stress on it before you make it, and work with an AI companion that uses the same commands you do.
MIT OR Apache-2.0. The browser version models and exports; stress analysis runs in the desktop app.
One program for the whole loop from an idea to a part you can trust.
Static stress on the part: pick the held faces and the loaded ones, and read the peak stress, the deflection and the safety factor against the material's yield.
Checked against beam theory: a 200 mm cantilever bends within 2% of P L³ / 3 E I.
An AI agent drives Polykrom through the same commands as the menus, over the Model Context Protocol, and checks what it built by measuring it.
Asked for a steel arm that carries 500 N at a safety factor of two, an agent designed a hollow tube that passed an independent check: SF 2.17, 0.165 mm, 198 g.
Polykrom is an MCP server. Point Claude Code, or any MCP client, at it and ask for a part. Headless, it runs its own design; with --connect it drives the open app so you can watch.
claude mcp add polykrom -- polykrom-cli mcp > Make an aluminium L-bracket, 80 × 40 × 50 mm, 5 mm thick, with two Ø8 holes, and tell me its mass.
Polykrom has its own icon language, Facet: each tool is a line drawing with one coloured facet, the face the command makes. The colour says what kind of work it is.