GPT-5.6 vs Claude Fable 5: Which Model Wins for Physical AI?

GPT-5.6 vs. Claude Fable 5 for Physical AI, which performs best?

We tested GPT-5.6 and Claude Fable 5 on five sealed physics modeling problems to see which handles real-world engineering best. While Claude Fable 5 achieved the highest accuracy, it came at a steep cost. The GPT-5.6 variants offered faster, cheaper results but struggled with complex verification. Our analysis reveals how each model's unique work style impacts reliability in critical physical simulations.