New featureModels ·
Claude Fable 5.1
Claude Fable 5.1
What it does
Anthropic's Fable 5.1 joined the selector, positioned for demanding reasoning, long agentic runs, and document work rather than prose alone.
Why it matters
It carries the widest reasoning range of any Claude in the selector, so the same agent can be run cheap or run deep.
The specs
Where Fable 5 was the writing model, 5.1 is pitched at long-running agentic work — coding, research, and document handling that chains many steps.
- Context
- 999,000 tokens in, up to 128,000 out.
- Input
- Text and images.
- Actions
- Supported.
- Reasoning
- Every level in the dropdown — Fast ($$), Smart ($$$), Smartest ($$$$), and Maximum ($$$$$).
- Plans
- Gold and Pro.