Claude Sonnet 4.5 (latest)

Claude Sonnet 4.5 is the latest entry in Anthropic's Claude Sonnet family, a mid-tier line designed to balance strong reasoning with the responsiveness and cost profile expected for everyday production use. Positioned as a refinement over prior Claude Sonnet releases, it continues Anthropic's emphasis on instruction following, nuanced language understanding, and reliable behavior in agentic settings where the model must plan, call tools, and stay coherent over long, multi-step interactions.

The model is multimodal on input, accepting text, images, and PDF documents, and produces text output, making it well suited to workflows that combine document understanding, visual reasoning, and written analysis or code generation. Its very large context window supports long documents, extended coding sessions, and multi-turn agent loops without losing track of earlier instructions. Practical strengths include tool calling, structured reasoning, and controllable generation, which together make Claude Sonnet 4.5 a strong fit for developer assistants, research and analysis pipelines, document Q&A, and other tasks that benefit from careful, step-by-step problem solving.