GearScript is a CSS-like language and a free browser studio: list the parts, say how they connect (hinges, gears, belts, pins) and drive one. The studio solves the rest and animates it in 3D. Built for people and AI alike: every error says how to fix it, and agents can check and verify projects through a CLI and MCP server. Export MP4, GIF or an interactive 3D page. No sign-up, nothing to install, open source.