A new Anthropic model is now available in the Kiro IDE and CLI for the AWS GovCloud (US) Regions. With Haiku 5.5, all three Claude 5.5 models are now available in Kiro in AWS GovCloud (US).

Claude Haiku 5.5 is the fastest model in the Claude 5.5 family. It’s a clear step up from Claude Haiku 4.5, built for work that runs in large volumes and needs quick responses. Developers can use it to summarize and compact long context, classify and route requests, process text in bulk, and make small, targeted edits across many files. It also works well as a review subagent that runs in parallel, while Opus 5.5 and Sonnet 5.5 take on harder planning and coding work. Haiku 5.5 uses adaptive thinking across five effort levels from low to max, with medium as the default. It’s available with a 1M context window and a 0.06x credit multiplier. Requests over 100K tokens are billed at a 0.3x multiplier.

Ensure your IDE or CLI is updated to the latest version, then restart it to access the new model from the model selector. For more details, visit the GovCloud documentation, the monitoring and tracking guide, or contact your AWS account team. To learn more about Kiro, visit the Kiro product page.