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.

Details
- 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.
Best for
Long-running coding and analysis that earlier models could not sustain in a single stretch.
When to use it
Hard engineering or deep knowledge work where Opus 4.8 stalls or needs constant steering.
Who benefits
Engineers, analysts, and researchers running complex, multi-step tasks.
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