Show HN: Hackerscad – Code-first CAD with MCP server for AI agents

Hackerscad is a free, open-source parametric CAD tool where the model is code: typing updates the 3D view, and mouse actions like filleting an edge write readable code into the file. It uses OpenCascade B-rep for exact solids and real threads, exports 3MF, STL, STEP or drawings, and supports unittest blocks plus a command line for checking, rendering and exporting in scripts or CI. It ships with an MCP server and an agent skill so AI coding assistants can model parts, check dimensions and render them in the user's window.