Anthropic Claude Sonnet 5.5 and Claude Opus 5.5 are now available on Kiro in AWS GovCloud (US)

New Anthropic Models Available in AWS GovCloud (US)

Two new Anthropic models are now available in the Kiro IDE and CLI for the AWS GovCloud (US) Regions:

Claude Opus 5.5

• New Capabilities: More capable than Opus 5, adaptive thinking on every request, 40% fewer tool calls, and about half the tokens of Opus 5.
• Context Window: 1M
• Credit Multiplier: 2.0x (down from Opus 5's 2.2x)

Claude Sonnet 5.5

• New Capabilities: Faster than Sonnet 5, real-world coding performance approaches Opus 5.5, clearer writing for better collaboration.
• Context Window: 1M
• Credit Multiplier: 1.3x

What to do

• Update your IDE or CLI to the latest version.
• Restart your IDE or CLI to access the new models from the model selector.

Source: AWS release notes

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