# Claude Opus 5.5

> Claude Opus 5.5 on LegalForecastBench: micro Brier 0.1454 across 387 units.

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

- Provider: Anthropic
- Reasoning: High
- Public release: 2026-09-22
- 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: 0.1454
- Equal-case Brier: 0.1476
- Accuracy: 77.3% (299 of 387)
- High-confidence predictions: 65, of which 0 were wrong

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