Kiro: Claude Opus 5.5 now available in AWS GovCloud (US)

October 9, 2026 Claude Opus 5.5 now available in AWS GovCloud (US) Claude Opus 5.5 is available in the Kiro IDE and CLI across both AWS GovCloud (US) Regions. Claude Opus 5.5 , Anthropic's most capable Opus model yet, is now available in the Kiro IDE and CLI across AWS GovCloud (US-East) and AWS GovCloud (US-West). It improves on Opus 5 for long-running agentic coding work and thinks adaptively on every request, deciding how much effort each task needs. It includes a 1M-token context window with a 2.0x credit multiplier , down from Opus 5's 2.2x. Update to the latest IDE or CLI version, then restart it to access the model from the model selector. Learn more -> { PREVIOUS } Claude Opus 5.5 Now Available { NEXT } Claude Opus 4.8 Now Available