Claude Fable 5

Anthropic's newest model available to the public, adapted from its restricted top-tier Mythos line and shipped with built-in safety guardrails.

Anthropic's highest-capability model released for general use, state of the art on nearly all tested benchmarks across software engineering, knowledge work, vision, and scientific research.
Runs coding and knowledge work for extended periods without intervention, and is the first Anthropic model to pass 90% on its internal benchmark of long-running analytical tasks.
Ships with safeguards that quietly route queries on cybersecurity, biology, chemistry, and health to Claude Opus 4.8 instead, which triggers in under 5% of sessions.
Included free on Pro, Max, Team, and seat-based Enterprise plans from June 9 through June 22. API pricing is $10 per million input tokens and $50 per million output tokens, double Opus 4.8.
A higher-access version, Claude Mythos 5, is the same model with some safeguards lifted, restricted to a small group of cyberdefenders and infrastructure providers.

Long-running coding and analysis that earlier models could not sustain in a single stretch.

Hard engineering or deep knowledge work where Opus 4.8 stalls or needs constant steering.

Engineers, analysts, and researchers running complex, multi-step tasks.

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