Claude Fable 5.1 Keeps the Fable 5 Price and Cuts Cache Reads to 25 Cents
Anthropic's 1 September 2026 model is generally available at 10 and 50 dollars per million tokens, with cache reads at 0.25.
Direct answer
Claude Fable 5.1 launched on 1 September 2026 at the same 10 dollar input and 50 dollar output prices as Fable 5. Cache reads are 0.25 dollars per million tokens. The context window is 1 million tokens and max output is 128,000.
Anthropic released Claude Fable 5.1 on 1 September 2026. The model card lists it as generally available, with retirement no sooner than 1 September 2027. The id is claude-fable-5-1 on the Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry, and Claude Platform on AWS.
Input stays at 10 dollars per million tokens and output at 50 dollars, the same headline rates as Fable 5. Cache reads are 0.25 dollars per million tokens. A five-minute cache write is 12.50 dollars and a one-hour cache write is 20 dollars. The batch API takes 50 percent off input and output. The context window is 1 million tokens, max output is 128,000, adaptive thinking is always on, and the default effort is high. The listed knowledge cutoff is June 2026.
What Anthropic says it is for
The card tells most workloads to start on Claude Opus 5, which is priced at 5 and 25 dollars. It points to Fable 5.1 when the job is long-horizon coding, multistep research, or document and spreadsheet work, or when Opus 5 at higher effort still misses the eval. Claude Mythos 5.1 is described as the same capabilities, limited to Project Glasswing.
The platform notes also say effort can change mid-conversation on Fable 5.1 without dropping the prompt cache, using a beta header. Thinking blocks from this model are kept for this model or a newer one. An earlier model cannot read them.
Source: Anthropic, Claude Fable 5.1.
FAQ
- Where can it be called?
- The model id claude-fable-5-1 is on the Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry, and Claude Platform on AWS.
- Who gets Mythos 5.1?
- Anthropic says Claude Mythos 5.1 has the same capabilities and is limited to Project Glasswing participants.