Claude Opus 4.5 (latest)

Anthropic's Opus line has historically targeted deep reasoning and extended autonomous task completion, and Claude Opus 4.5 continues that direction as a frontier-tier model. It is positioned for complex software engineering, multi-step agentic workflows, and long-horizon computer use, reflecting a deliberate emphasis on sustained, tool-driven problem solving rather than lightweight chat. The model accepts text, images, and PDFs as input while producing text-only output, making it well suited to pipelines that need to ground language reasoning in attached documents, screenshots, or diagrams alongside structured tool calls and temperature-controlled generation.

OpenRouter surfaces Claude Opus 4.5 through multiple upstream providers, which improves availability for production deployments and gives teams flexibility in routing. In head-to-head comparison data, it scores at the top of the reasoning band while showing more conservative coding, multimodal, and cost-efficiency scores relative to a sibling Sonnet-class model, suggesting it is best deployed where depth of reasoning and tool orchestration matter more than raw price-performance. The 200,000-token context window paired with a 64,000-token output ceiling supports long agentic trajectories, large code or document analysis sessions, and retrieval-heavy workflows that need to maintain state across many turns.