Anthropic's latest AI model successfully built a fully functional game in a single session, demonstrating a significant leap in the model's ability to handle complex, real-world creative tasks.

What happened: Anthropic released a new model, and a developer used it to create a complete game called Shepherd's Dog in one attempt. The model produced a 2,319 line HTML file with zero dependencies after a reasoning session lasting 45 minutes and consuming more than €20 worth of tokens.

Why it matters: This marks the first time the developer was able to get an AI model to create a fully functional game from concept to completion in a single shot—something that had not succeeded with earlier models. The result matched the developer's original vision, suggesting the model has reached a new threshold for handling intricate, multi-step creative and technical work.

What to watch: The completed game is playable at vnglst.github.io/when-ai-fails/shepards-dog/claude-fable-5/index.html, and the developer's repository shows previous unsuccessful attempts with earlier models, providing a concrete benchmark for how much capability has improved.