PRODUCTION SCENARIO
After moving a summarization service from Claude Sonnet 4.6 to Claude Opus 5, every request fails with a 400 error saying thinking.type.enabled is not supported for this model.
What change keeps extended reasoning working on the new model?
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Answer: Set thinking to type adaptive and control depth with output_config.effort
Claude 4.7 and later models reject manual extended thinking with a 400; the documented migration removes budget_tokens, sets thinking to adaptive, and moves depth control to output_config.effort. Budget and header tweaks do not make the removed mode available.