Claude Fable 5.1
The most demanding reasoning and long-horizon agentic work.
Claude Fable 5.1 supersedes Claude Fable 5.
What are Claude Fable 5.1's specs and price?
Claude Fable 5.1, built by Anthropic, ships a 1M-token context window and a 128K-token max output, released 2026-09. It supports text and vision input with a dedicated reasoning mode and costs $20.00 per million blended tokens, the 42nd-cheapest of 42 models we track.
What are Claude Fable 5.1's specs?
| Context window | 1M tokens |
| Max output | 128K tokens |
| Modalities | text, vision |
| Extended thinking | Yes |
| Released | 2026-09 |
| Knowledge cutoff | 2026-06 |
| Provider | Anthropic |
Verified 2026-08-14 — source.
Where does Claude Fable 5.1 rank?
What are Claude Fable 5.1's strengths?
- Most capable widely-released Claude
- 1M-token context
- Extended-thinking mode for hard reasoning
What else should you know about Claude Fable 5.1?
What are common questions about Claude Fable 5.1?
What is Claude Fable 5.1's context window?
Claude Fable 5.1 has a 1M-token context window and a 128K-token max output — the 12th-largest context of the 42 current models we track. Source: https://docs.anthropic.com/en/docs/about-claude/models, verified 2026-08-14.
Does Claude Fable 5.1 support vision or audio input?
Yes — Claude Fable 5.1 accepts vision input in addition to text.
Does Claude Fable 5.1 have a reasoning or extended-thinking mode?
Yes — Claude Fable 5.1 exposes a dedicated reasoning mode for multi-step problems.
When was Claude Fable 5.1 released, and what is its knowledge cutoff?
Claude Fable 5.1 was released 2026-09 with a knowledge cutoff of 2026-06.
How much does Claude Fable 5.1 cost, and who provides it?
Claude Fable 5.1 is served by Anthropic at $20.00/M blended tokens (3:1 input:output) — the 42nd-cheapest of 42 current models. Full pricing breakdown: /llm-api-pricing/claude-fable-5-1.