Anthropic introduces Claude Fable 5.1 and restricted Mythos 5.1
Anthropic released one underlying model through two safeguards: Fable 5.1 is generally available, while Mythos 5.1 is limited to vetted cyber-security and life-science partners. Fable is offered across Anthropic, AWS, Google Cloud and Microsoft Azure at US$10 per million input tokens and US$50 per million output tokens; cache reads are US$0.25 per million.
Why it matters: The split distribution model is an important governance experiment: capabilities and access controls can be separated without maintaining different base models.
Business/technical/strategic impact: Enterprises gain stronger frontier capability but should independently test safety, latency and total cost. Anthropic’s cost-reduction and benchmark figures are vendor claims; Exact Foundation Snapshots are promised later in the northern autumn and are not yet generally available.
