# Claude Fable 5.1

> Claude Fable 5.1 on LegalForecastBench: micro Brier 0.1288 across 387 units.

Canonical: https://www.legalforecastbench.org/models/claude-fable-5-1/

- Provider: Anthropic
- Reasoning: Adaptive thinking (provider default)
- Public release: 2026-09-01
- Training cutoff: June 2026 (training-data cutoff)
- Eligibility: eligible. The reported training-data cutoff (June 2026) is in the month of the first scored decision (June 30, 2026). It is treated as preceding that decision, because a ruling is very unlikely to enter training data the day it issues.
- Micro Brier: 0.1288
- Equal-case Brier: 0.1365
- Accuracy: 82.2% (318 of 387)
- High-confidence predictions: 81, of which 0 were wrong

Ranked comparison: https://www.legalforecastbench.org/#leaderboard