Every line of code in Frag Foundry was written by Claude, Anthropic's AI — in a 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, built each one, then art-directed the look.

The sound and music are synthesized live with Web Audio, and the bots aim with real raycasts. Claude built the whole thing and gathered everything it needed as it went — the human wrote none of the code and touched none of the build. AI-built, start to finish.