Simon Willison one-shot a 3D browser game with Claude Fable 5 and concluded taste is the remaining human part.

From two images in a 2024 tweet plus one instruction ("Work independently, do not ask me to make any further design decisions... Commit and push as often as possible"), it built a playable 3D raccoon stealth game with guards, a scent-tracking dog, a police cruiser, speed pickups and three nights of escalating difficulty, deployed to GitHub Pages, self-verifying with Playwright screenshots and generating textures via OpenAI's image API. His verdict: engineering "a very impressive starting point," gameplay "mediocre" and "very, very easy." Autonomous multi-hour builds clear the implementation bar now. Designing something fun is what's left.