A few days ago, Anthropic released the model that was supposedly too dangerous for the world to see. I wanted to give it a try using my personal benchmark: can it build a game idea I've had for years, in a single shot?

The model started with a very long reasoning session, and after 45 minutes and more than €20 worth of tokens (!), it happily reported that "Shepherd's Dog is complete — a single 2,319 line index.html with zero dependencies."

You can watch the video below or give the game a try It's really fun and exactly how I imagined it. For me this is the first time an AI model is able to create this for me in one go:

Play the game here: vnglst.github.io/when-ai-fails/shepards-dog/claude-fable-5/index.html

Other attempts with earlier models: github.com/vnglst/when-ai-fails/blob/main/shepards-dog/README.md