Claude Fable 5.1 Pricing: What Anthropic's Frontier Model Actually Costs

What Is Claude Fable 5.1? Claude Fable 5.1 is Anthropic ‘s current frontier-tier model, released in September 2026 alongside a companion version called Claude Mythos 5.1. Both run on a 1 million token context window with a maximum output of 128,000 tokens, and both cost exactly the same to use: $10 per million input tokens, $50 per million output.