Anthropic launched Claude Fable 5.1 on September 1 (API id claude-fable-5-1) for Pro, Max, Team, and Enterprise, plus the Claude API, AWS, Google Cloud, and Microsoft Foundry. List price stays $10 input / $50 output per 1M tokens, but cache reads drop to $0.25 (75% less than Fable 5), which Anthropic estimates cuts typical workloads about 25% and highly agentic ones up to about 45%. Claude Mythos 5.1 remains limited to trusted-access programs.

Key Takeaways

  • βœ“Fable 5.1 is GA for Pro/Max/Team/Enterprise and the API as claude-fable-5-1.
  • βœ“List price stays $10/$50 per 1M tokens; cache reads are $0.25, about 25% cheaper typical jobs and up to ~45% on heavy agent workloads.
  • βœ“Mythos 5.1 stays trusted-access only. Fable 5.1 targets long-horizon coding; Devin said it is moving Opus 5 traffic onto it at launch.
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