Claude Mythos 5
AssessPlatforms
An Anthropic AI model documented alongside Claude Fable 5 in the published system card.
Why it's here
Placed in Assess: 2 article(s) of evidence from 3 source(s), led by model releases, with 2 in the last 30 days. Confidence 44%.
Evidence (2)
- 8Simon Willison·6/9/2026model_releaseInitial impressions of Claude Fable 5
The article gives early hands-on impressions of Anthropic's Claude Fable 5, describing it as very capable but also slow and expensive. It highlights a 1 million token context window, a 128,000-token output limit, stricter safety guardrails than Claude Mythos 5, and a new fallback mechanism when requests are rejected.
- 6TechCrunch AI·6/9/2026model_releaseAnthropic Releases System Cards for Claude Fable 5 and Claude Mythos 5
Anthropic published system cards for Claude Fable 5 and Claude Mythos 5, documenting the models' behavior, safety evaluations, and deployment characteristics. The PDF is a model release report rather than a product announcement, aimed at providing transparency into capabilities and limitations.