Anthropic ships Claude Fable 5.1 with ~25% lower typical costs

Anthropic released Claude Fable 5.1 and Mythos 5.1 on September 1. Base pricing is unchanged at $10 and $50 per million input and output tokens; the roughly 25% saving on typical workloads comes from cache reads costing 75% less, rising to about 45% on agentic work. Agentic science scores more than doubled, 24.7% to 52.6%; other benchmarks gained more modestly.