Anthropic has unveiled Claude Sonnet 4.5, a new frontier AI model designed to deliver state-of-the-art coding performance and reliability. Available through the Claude API and chatbot at the same pricing as its predecessor, the model is positioned to build full production-ready applications, moving beyond the prototype stage.
Anthropic reports Claude Sonnet 4.5 achieves leading results on benchmarks such as SWE-Bench Verified and demonstrates long-horizon coding capabilities in enterprise trials, autonomously managing tasks from app development to database setup and compliance audits. Tech leaders including Cursor CEO Michael Truell and Windsurf CEO Jeff Wang praised its performance. Alongside the launch, Anthropic introduced the Claude Agent SDK and a research preview, “Imagine with Claude,” further extending its developer ecosystem amid intensifying competition with OpenAI.
