Claude Fable 5.1
Anthropic · Claude 5 · closed weights
Facts and where they come from
| Released | 2026-09 | labofficial docsmodel page: released September 1, 2026 |
|---|---|---|
| Licence | proprietary | labofficial docsweights not published |
| Total parameters | not disclosed | not disclosed |
| Active parameters | not disclosed | not disclosed |
| Context length | 1,000,000 tokens | labofficial docsmodel page: context window 1M tokens |
Architecture
not disclosed No diagram or modelled costs: Anthropic has not disclosed the architecture or size.