Glossary term
Mythos-class
Also: Mythos tier, Mythos class
Mythos-class is Anthropic's official designation for its top model tier, positioned above Opus and covering both the Mythos Preview and Mythos 5.
Where it sits
Mythos-class ranks above Opus in Anthropic's lineup and represents the most capable models the company has shipped. It is the umbrella term for the April 2026 Mythos Preview and the Mythos 5 release of June 9, 2026.
Not "Capybara"
A pre-launch internal-rumor label, "Capybara tier," was mistakenly treated as the product name. The correct term is Mythos-class; "Capybara" was never official.
Sources & further reading
- Anthropic — Fable & Mythos access noticeOfficialanthropic.com
Facts on this page link to their source. Quotes are kept under 15 words and attributed; figures labelled unofficial are third-party until Anthropic publishes system-card numbers.