Anthropic

Claude Sonnet 4.5

Anthropic's latest mid-size model, part of the Claude 4.5 series, evaluated with up to 32,000 reasoning tokens.

creatorAnthropic
date2025-09-29
accessibilityClosed weights
Rank: 39/200147Epoch Capabilities Index
About ECI90% CI: 143-152
Claude Sonnet 4.5 performance
Top performing model