model

Claude Mythos 5.1

Capability twin of Fable 5.1 restricted to Anthropic's trusted access program; notably does not run the prefix-binding check.

Known aliases

Mythos 5.1

Relationships

No evidence-backed relationships are recorded.

Current clusters

leadership1 distinct publisher

Anthropic cuts Fable 5.1 prices by 25% and launches two-tier safeguard system with Mythos 5.1

The saving comes off cache reads, so it lands unevenly across teams, and the model's most sensitive capability now reaches users through a credential issued by an access program, not a purchase order a budget holder can sign off alone. Both changes move the decision away from the budget holder.

Publishers:anthropic.com

Reality

Evidence28
Adoption24
Hype gap+34
Incentives86

build2 distinct publishers

Anthropic cuts Fable 5.1 cache reads to a fortieth of its input price

List prices stay at $10 and $50 per million, so the only lever that moved is the one that rewards a byte-stable prompt prefix, and Fable 5.1's new thinking-block binding rules decide whether yours stays stable.

Publishers:platform.claude.comthenewstack.io

Reality

Evidence62
Adoption34