Simon Willison Tests Claude Fable 5 by Building a Raccoon Heist Game

On August 5, 2026, Simon Willison published an account of using Anthropic's Claude Fable 5 (running in Claude Code for web) to build a complete 3D browser game from a single prompt. The project was inspired by a tweet from August 5, 2022, in which Willison shared a game concept generated by GPT-3 and concept art from DALL-E. On the fourth anniversary of that tweet, he decided to see if Claude Fable 5 could turn the original screenshots into a playable game. The resulting game, titled 'Raccoon Heist', features a team of raccoons pulling off heists, and is available on GitHub Pages. Willison provided the AI with a detailed prompt, including instructions to use an OpenAI API key for generating textures via gpt-image-2, to work independently, and to commit and push changes frequently. The AI used Three.js for 3D rendering, generated textures and a title screen, and even added a guard dog as a new mechanic. The game includes features such as collecting items, avoiding guards and a dog, and a day-night cycle. Willison notes that while the game is technically impressive, it is not particularly fun or challenging, and he reflects on the limitations of AI in game design. The project is documented in a notes.md file, and the full build log is available. Willison also discusses his workflow, including using GitHub Pages for previewing and the use of his claude-code-transcripts tool.