Adds beta dynamic workflows for Managed Agents and documents additional Haiku 5.5 incompatibilities

computer_20250124 also returns a 400 error: use the computer_toolset_20260801 toolset on the Claude API and Google Cloud, or computer_20251124 on Amazon Bedrock.

You can now let a Claude Managed Agents agent use dynamic workflows, in beta with the managed-agents-2026-04-01 beta header.

Manual extended thinking (budget_tokens), the sampling parameters temperature, top_p, and top_k, and assistant message prefill can each return a 400 error.

A request that sends thinking blocks back after a change to system, tools, or earlier turns can also return a 400 error. On Amazon Bedrock, structured outputs aren't available for Claude Haiku 5.5.

Adaptive thinking is on by default, so a response can begin with thinking blocks, and their text is omitted unless you set thinking.display to "summarized".