Anthropic releases Fable and Mythos 5.1

Anthropic released Fable 5.1 and the partner-only Mythos 5.1, saying the models generated three scientific findings before release. TechCrunch’s release report says Fable is available through Anthropic’s API and cloud platforms, while Mythos remains limited to cybersecurity and life-science partners. Builders testing frontier models should separate access from autonomy: the archive’s earlier Fable analysis flagged guarded deployment as the product, not a footnote.