Baba Is Solved by Fable 5 and GPT-5.6 Sol, but at what cost?

GPT-5.6 Sol and Claude Fable 5 solved almost all levels in the first two stages of Baba Is You, but took significantly longer than humans. The benchmark, Baba Is Harbor, cost over $2000 in experiments and revealed surprising cost disparities, e.g., Gemini 3.5 Flash was 2.4x more expensive than Fable 5 for the same stage.