Claude Fable 5.1
ECI#5
165Claude Fable 5.1 is a closed-weights model from Anthropic, released September 1, 2026. It has an ECI score of 165 and ranks 5th of 257 tracked models. At the time of its release, it ranked 1st of 247 tracked models.
Claude Fable 5.1 vs select alternatives
| Domain | Benchmark | Claude Fable 5.1 | |||
|---|---|---|---|---|---|
ECI scoreBest score 167 | 165 | 163 | 162 | 157 | |
| Ranking | #5 | #6 | #8 | #15 | |
| Conceptual reasoning | ARC-AGI-2Best score 95% | ||||
| Games | Chess PuzzlesBest score 72% | ||||
Earthborne Rangers (EBR-bench)Best score 76% | |||||
Mystery Game PuzzlesBest score 84% | |||||
| Mathematics | FrontierMath Tiers 1-3 (v2)Best score 94% | ||||
FrontierMath Tier 4 (v2)Best score 100% | |||||
OTIS Mock AIME 2024-2025Best score 100% | |||||
| Multimodal | Furniture Assembly BenchmarkBest score 83% | ||||
| World knowledge | SimpleQA VerifiedBest score 76% |
