Claude 3.7 Sonnet vs Claude Sonnet 4.6

Claude 3.7 Sonnet

Anthropic

Claude Sonnet 3.7, released by Anthropic in February 2025, is a large language model from the Claude 3 family featuring hybrid reasoning with configurable extended thinking. It supports a 200K token context window, 64K maximum output tokens (128K in beta), and native image understanding. Sonnet 3.7 targets complex coding, mathematics, and scientific reasoning tasks where extended chain-of-thought processing provides meaningful improvements in output quality.

Claude Sonnet 4.6

Anthropic

Claude Sonnet 4.6 is a general-purpose language model from Anthropic, released in February 2026 as an update to the Sonnet 4 line that introduced adaptive thinking — a mode where the model automatically calibrates its reasoning depth based on task complexity rather than requiring manual configuration by the developer. The model accepts text and image inputs and integrates natively with web search and code execution tools, consolidating capabilities that previously required separate toolchain setup into a unified API surface. It became the primary workhorse model in the Claude 4 series for code assistance, agentic pipelines, and retrieval-augmented applications that benefit from built-in web access.