Breaking
Anthropic releases Claude Fable 5.1 and Mythos 5.1
Claude Fable 5.1 is now available through Anthropic, AWS, Google Cloud, and Microsoft Azure. Claude Mythos 5.1 uses the same model with stricter safeguards, and Anthropic is keeping it inside trusted access programs.
What happened
Anthropic released Claude Fable 5.1 for general use. It also released Claude Mythos 5.1 for restricted cybersecurity and life sciences work. Developers can use claude-fable-5-1 through the Claude API. Cache reads now cost $0.25 per million tokens, down 75%. Other Fable 5 pricing remains unchanged.
Why it matters now
Claude Fable 5.1 gives Anthropic a new model and pricing baseline. Anthropic says typical token-billed workloads cost about 25% less than Fable 5, based on four weeks of August usage. That is Anthropic's estimate, not an independent measure. Mythos 5.1 is still not generally available.
Updates
What changed
Anthropic releases Claude Fable 5.1 and Mythos 5.1
Claude Fable 5.1 is now available through Anthropic, AWS, Google Cloud, and Microsoft Azure. Cache reads cost 75% less. Claude Mythos 5.1 remains limited to trusted access programs.
Verification
Primary evidence before publication.
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