Anthropic has released Fable 5.1 across its platforms and major clouds at $10 per million input tokens and $50 per million output tokens, while cutting cache reads to $0.25 per million tokens.
What you need to know
- Fable 5.1 is generally available across Anthropic and major cloud platforms
- $10/M input, $50/M output and $0.25/M cache reads
- Mythos 5.1 remains a restricted professional-access tier
One model family, two access envelopes
Fable 5.1 is the product most teams can evaluate now. Anthropic lists access through Claude, its API, AWS, Google Cloud and Microsoft Azure. Mythos uses the same underlying model but is reserved for vetted cybersecurity and life-sciences organisations, so it should not be presented as a normal self-service alternative.
The cache change is the commercial story
Headline input and output rates remain premium, but cache reads fall to $0.25 per million tokens. Teams running persistent agents or repeatedly loading a large codebase should compare total task cost with and without context reuse rather than judging the release from the standard token price alone.
Why HubAI is withholding a score
Launch claims and vendor benchmarks are not an independent test. HubAI will score Fable only after identical coding, research and document tasks are run against relevant OpenAI and Google alternatives with completion rate, correction time and total cost recorded.
HUBAI VIEWFor persistent agents, context-reuse economics may matter more than the unchanged headline token price.
Buyer decision signal: New model · buyer comparison
What to verify next
1Confirm access on the required Claude or cloud plan
2Verify context and output limits
3Measure cache hit rate on a real workflow
4Record total cost per accepted task
5Keep Mythos marked as restricted access
Read the evidence
Capabilities, availability and prices can change. HubAI keeps analysis separate from the underlying official material.
01Anthropic: Claude Fable 5.1 and Mythos 5.1Open source ↗
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