Anthropic Publishes System Cards for Fable 5.1 and Mythos 5.1

Anthropic published system cards for Fable 5.1 and Mythos 5.1, confirming they share one base model with different safety guardrails. Mythos 5.1 serves vetted cybersecurity and life-science users via trusted access, alongside a life-sciences verification program with the US government.

2026-09-02 ~ 2026-09-02 · 4 related posts

• Anthropic releases System Cards for Fable 5.1 and Mythos 5.1 — scaling01 · 2026-09-02
• Anthropic: Fable 5.1 and Mythos 5.1 Are Identical — BLUECOW009 · 2026-09-02
• Anthropic launches Mythos 5.1 for cybersecurity and life sciences — minchoi · 2026-09-02
• Anthropic launches Mythos 5.1 with Life Sciences Verification Program — arjunrajlab · 2026-09-02