Anthropic's Fable 5.1 is cheaper and less restrictive

Anthropic’s new Fable release is cheaper, less restrictive

Anthropic bumped Fable and Mythos to 5.1. Fable 5.1 is now cheaper and triggers fewer false-positive safety refusals; it's live today on cloud platforms and the API. Mythos 5.1 remains restricted to registered cybersecurity and life sciences partners. A key change is zero data retention—clients can run the model on their own infra with no data outflows, rolling out this fall. The post doesn't disclose specific price cuts or benchmark comparisons.

Why it matters: Anthropic updates both Fable and Mythos lines simultaneously — Fable gets cheaper with fewer false refusals, Mythos stays gated. Zero data retention is the hardest new fact here, but the post doesn't disclose specific price cuts or refusal-rate numbers, so the score stays at 78.