Opening
Our most capable model for cybersecurity and biology research.
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- Words
- 786
- Reading time
- 4 min
- Last crawled
- 2026-09-26
- Cited by
- 1 of their pages
- Language
- EN
Announcements
NEW Introducing Claude Mythos 5.1 Sep 1, 2026 Claude Mythos 5.1 is our newest Mythos-class model, with gains in cybersecurity and biology. Access remains limited to a small set of vetted organizations. Read more - Claude
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Availability and pricing
Claude Mythos 5.1 is available to vetted cyberdefenders and life scientists through our trusted access programs. The Life Sciences Verification Program is launching as an invite-only beta offering access with reduced bio
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Safeguards
Because Mythos 5.1 is highly capable for cybersecurity and biology research, it could be used both for good and for harm. We currently only provide access to a small, but growing, set of vetted organizations through our
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Data retention
Using Claude Mythos 5.1 requires accepting a 30-day data retention policy for safety monitoring by default. Learn more.
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Benchmarks
Claude Fable 5.1 and Claude Mythos 5.1 are the same underlying model. Results below are for Fable 5.1 unless noted; where Mythos 5.1 results are shown, the gap reflects tasks where Fable 5.1’s safeguards intervene. Fable
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