Anthropic hints at Claude Mythos 5.5 for cybersecurity and biology research

A hidden reference on Anthropic's website lists Mythos 5.5 as its most capable model class for high-stakes research Anthropic may have a new top-tier model in the works, and it surfaced in the quietest way possible. A hidden reference on the company’s website lists Claude Mythos 5.5 as Anthropic’s most capable model class for cybersecurity and biology research. There was no keynote and no launch blog post. A single line of text tucked into a webpage carried the news. What the reference shows, and what it does not The listing places Mythos 5.5 at the top of Anthropic’s lineup for two specific fields: cyber defense and biological research. Both are classic dual-use domains. The same knowledge that helps patch a vulnerability can help exploit one. The reference does not include a release date, pricing, or access details. The version number does slot neatly into Anthropic’s existing sequence. The company already has Mythos 5 and Mythos 5.1 on the record. How the Mythos tier works Anthropic introduced its Mythos-class models in June 2026, launching Mythos 5 alongside a sibling called Fable 5. Mythos is the restricted version. It is available only to selected, vetted partners working in ...