Anthropic Ships Claude Fable 5.1, More Than Doubling Its Predecessor on Key Benchmark

Decrypt · 2026-09-01T19:29:12.000Z

Fable 5.1 and its restricted sibling Mythos 5.1 arrive three months after export controls forced Anthropic to pull Fable 5 offline for 18 days

Source: Decrypt · 2026-09-01T19:29:12.000Z · fact-reporting