Anthropic
Claude Fable 5.1 (Adaptive Reasoning, Max Effort, Default Fallback)
Claude Fable 5.1 improves on Fable 5 across long-running agentic coding, knowledge work, and research, following instructions precisely over sessions that run unattended for hours.
Claude release notesModel Snapshot
TypeLanguage
ReleaseAug 31, 2026
Context1,000,000
Tagsreasoning, tool-use, explicit-caching, file-input
Overall
Rank #6 across 687
53.4
Coding
Rank #1 across 330
81.6
Blended Price
Rank #414 across 432
$20.00/M
Strength Profile
Percentile score by analysis domain.
* Cost is inverted: lower input, output, and blended prices rank higher.
Benchmark Percentiles
Higher bars mean stronger relative placement.
Model Details
Runtime
Output Speed64.9 tok/s
First Token122.47s
Max Output128,000
Pricing
Blended$20.00/M
Input$10.00/M
All Benchmarks
| Metric | Domain | Value | Rank |
|---|---|---|---|
| Artificial Analysis Intelligence Index | overall | 53.4 | #6 |
| Artificial Analysis Coding Index | coding | 81.6 | #1 |
| LiveBench Mathematics | math | 97.0% | #2 |
| GPQA | reasoning | 93.7% | #11 |