Claude Fable 5.1 officially launches on the B.AI API, built for complex reasoning and Agent workflows.
Source：
x.com
The B.AI platform announced that Anthropic's latest Mythos-class general-purpose model, Claude Fable 5.1, is now officially available via API. Built on the same underlying model as Claude Mythos 5.1, it is deeply optimized for high-intensity coding, long-running Agent workflows, and complex knowledge tasks, achieving an outstanding performance of 73.4% at maximum compute intensity in the CursorBench 3.2.0 evaluation.
