Claude Sonnet 5.5 is now available in Kiro

Claude Sonnet 5.5 is available today across Kiro IDE, CLI, Crew, and Web. It is Anthropic’s fastest Sonnet model to date and a clear upgrade over Claude Sonnet 5. In our internal benchmarking, Sonnet 5.5 performed better than Sonnet 5, while being more efficient in both token usage and speed.