Developer builds Sedmice AI opponent using GPT-5.6 Sol and Claude Fable 5

Two days before the post, a developer learned the traditional Slovenian card game Sedmice from a friend. To settle arguments about optimal moves, they wrote out rules, architecture, AI constraints, and implementation details, then handed the project to GPT-5.6 Sol. Within roughly two hours, Sol produced a working prototype with correct rules and a playable AI opponent. The developer notes that Sol has improved considerably at UI and UX, but still isn't perfect. They then used Claude Fable 5 to refine the prototype into a full product. The post serves as a user impression of both models, demonstrating practical use for rapid prototyping and productization.