Glossary term
Fable (name origin)
"Fable" derives from the Latin fabula, 'that which is told,' a cousin of the Greek mythos, and names the safeguarded public edition of the Mythos-class model.
The etymology
Fabula in Latin means "story" or "that which is told," sharing semantic roots with the Greek mythos. The naming pairs Fable (the public edition) with Mythos (the unrestricted tier) as two tellings of the same model.
What Fable 5 is
Fable 5 is the same underlying model as Mythos 5, shipped with safety classifiers. When those classifiers flag a request, Fable 5 reroutes it to Claude Opus 4.8 and tells the user.
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.