Claude 3.7 Sonnet — Introduced

Anthropic introduced Claude 3.7 Sonnet on February 24, 2025, as the next major evolution of the Claude Sonnet family. It was presented as a hybrid reasoning model, capable of giving fast responses for simpler tasks while also using extended thinking for more complex problems. A major feature of Claude 3.7 Sonnet was its extended thinking capability, which allowed the model to spend additional computational effort working through difficult questions before producing an answer. This made it particularly useful for advanced reasoning, mathematics, coding, and complex problem-solving. Claude 3.7 Sonnet also brought improvements to software engineering and agentic coding tasks, allowing it to work through multi-step programming problems more effectively. It represented an important shift toward AI models that could combine normal conversational responses with deeper reasoning when needed.