Every line of code, every texture, every sound in Frag Foundry was written from scratch by Claude, Anthropic's AI — in a single working session, play-testing itself in the browser as it went. No engine editor. No human-written code.

A person described the game they wanted — a fast arena shooter that runs in a browser on a Mac — and Claude took it from there: it wrote a design document, broke the work into phases, and built each one.

The textures are painted onto canvases when the page loads. The sound and music are synthesized live with Web Audio. The bots aim with real raycasts. Every arena, weapon, and pixel was generated here, not sourced from anywhere. One HTML file. Zero slop.