Claude Fable 5 Builds a 100-Player Browser Battle Royale From One Prompt

A developer who tested Anthropic's latest model "Claude Fable 5" on its "max effort" setting has released a demo in which a single-sentence prompt produced a playable 100-player browser-based battle royale game. The case has drawn industry attention as an example of generating a full game from one written instruction. In related evaluations, the model was compared against other AIs such as ChatGPT, Gemini and Grok, with Fable 5 finishing a Fortnite-style battle royale island in about an hour and a half and presenting a playable 16-player version in some cases.