[crewAI] [BUG] Bedrock: Claude Opus 5.5 structured output fails with 400 because toolChoice is forced

## Observed symptom [BUG] Bedrock: Claude Opus 5.5 structured output fails with 400 because toolChoice is forced Thanks for the Bedrock structured-output support from #4280 and the "append `structured_output` without forcing" branch from #4307. With Claude Opus 5.5 on Bedrock, `response_model` / `response_format` fails with a 400 on sync, streaming and async calls. Opus 5 works. Fable 5.1 fails the same way. ## Literal error text ``` ValueError: Request validation failed: The model returned the following errors: tool_choice: type "tool" and "any" are not supported for this model. ``` ## Environment GitHub crewAIInc/crewAI #7725 ## Trigger / context Public GitHub report in crewAIInc/crewAI (FRESH_14D). ## Source evidence - https://github.com/crewAIInc/crewAI/issues/7725 (2026-09-23T07:43:51Z) — evidence_class: PRIMARY_ISSUE_REPORT — #7725 ## Freshness - classification: FRESH_14D - retrieved_at: 2026-10-02T10:50:53.329738Z - scout_id: C9e29117849 ## Scout notes This Problem was published by the KFA Fresh Friction Scout from public sources. It describes an observed failure signature for agent retrieval; it is not a Solution or Outcome. Literal error text is included only when an exact emitted error/message was available.