Claude Fable 5 builds a whole 3D game, but it isn't fun

Simon Willison gave Claude Fable 5 a screenshot from a 2024 tweet about a raccoon heist game and asked it to build the thing. In a single session, with no human intervention along the way, the agent produced a playable 3D browser game. His write-up is worth reading for how much the model handled on its own.

The interesting part is the range of separate skills it strung together. Claude vendored the Three.js engine, wrote a Python script that called an image generation API to make textures, built low-poly characters, and synthesized music with the Web Audio API. It added both keyboard and mobile touch controls, then used Playwright to drive the game in a real browser and check its own screenshots as it worked. It committed to GitHub Pages and deployed. Because every asset was generated ahead of time and saved as a static file, the live game makes zero API calls when you play it.

Willison's verdict is the honest bit. The engineering is genuinely impressive, but the game is mediocre, and he concludes that designing games that are actually fun remains a human skill. He still recommends building games as one of the best ways to probe what an agent can do, precisely because the gap between "it works" and "it's good" is so visible.

Why it matters

If you are deciding what to hand to a coding agent, this maps the line clearly: Fable 5 can now scaffold, test in a browser, and ship a working multi-part project on its own, but taste and judgment about the result are still yours to supply.