Sonnet 5.5

Claude Sonnet 5.5, the second model in the Claude 5.5 family, offers a significant upgrade over Sonnet 5, running 30%+ faster and costing up to 30% less. It introduces safety classifiers to prevent reasoning extraction, a first for a Sonnet model, and expands preserved thinking to prevent decoupling Claude’s thinking from the creating account. Sonnet 5.5 demonstrates improved performance across various benchmarks, including agentic coding, knowledge work, multidisciplinary reasoning, computer use, and visual chart recognition.