Claude Opus 4.1

Claude Opus 4.1 is designed as a hybrid reasoning model, capable of delivering both quick responses and deliberate step-by-step analysis depending on the task. This architecture makes it well-suited for agentic workflows, complex software engineering, and research-level synthesis across external data sources. The model shows particular strength in multi-file code refactoring, precise bug identification within large codebases, and maintaining detail tracking across long, tool-assisted tasks. Developers can tune "thinking budgets" via API, balancing depth of reasoning against cost and latency based on their specific needs.

The release brings measurable gains across benchmarks—most notably a 74.5% score on SWE-bench Verified, surpassing its predecessor by two percentage points. Industry testers confirm these improvements translate to real-world utility: Windsurf reports roughly a one-standard-deviation jump over Opus 4 on their junior developer benchmark, while Rakuten Group notes the model's precision in locating exact corrections without unnecessary changes makes it their team's preferred tool for daily debugging. Opus 4.1 maintains pricing parity with Opus 4 while offering a seamless upgrade path for existing users. Anthropic has signaled this release is the first of several substantial improvements planned in the coming weeks.