Fable 5.1 is a massive upgrade, but the bigger story is how much cheaper it is. Cache reads in particular are 75% cheaper! This puts it much closer to the pricing of GPT-5.6-Sol, while being a much more capable model.

Claude@claudeaiSep 1

Cache reads with Fable 5.1 cost 75% less than Fable 5’s. This reduces the cost of the model in practice by around 25% for typical workloads, and up to 45% for highly agentic ones. https://t.co/uGjoKHcbOD