Anthropic ships Haiku 5.5 through Claude API and cloud platforms

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Haiku 5.5 is Anthropic's model for high-volume, latency-sensitive work. It is available through the Claude API, Amazon Bedrock, Claude Platform on AWS, Google Cloud, and Microsoft Foundry.

Here's what changed:

• Haiku 5.5 supports a 1M-token context window and up to 128k output tokens.
• Adaptive thinking is enabled by default, with effort controls. Set thinking.display to "summarized" to receive thinking text, which counts toward token usage.
• OpenTelemetry export is in beta for tracing Messages API requests and Managed Agents sessions.
• Scheduled Claude Managed Agents deployments are available on Claude Platform on AWS.

One catch: Migration requires checking existing calls. Manual extended thinking, some sampling parameters, assistant message prefill, and the older computer-use tool can return 400 errors. Haiku 5.5 also lacks structured outputs on Bedrock.

Try it: Use claude-haiku-5-5 through the Claude API.

Sources: platform.claude.com