thinking-troubleshooting changedbuild-with-claude/thinking-troubleshooting
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## A 400 error after sending `thinking: {type: "disabled"}` ## A 400 error says `"thinking.type.disabled"` is not supported
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5858Switch the request to `thinking: {type: "adaptive"}` and steer thinking depth with `effort` instead of `budget_tokens`. [Migrating to adaptive thinking](https://platform.claude.com/docs/en/build-with-claude/extended-thinking#migrating-to-adaptive-thinking) walks through the conversion.
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60## A 400 error says `"thinking.type.disabled"` is not supported
60## A 400 error after sending `thinking: {type: "disabled"}`
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6262The request fails with a 400 error. On Claude Fable 5.1, Claude Mythos 5.1, Claude Fable 5, Claude Opus 5.5, and Claude Mythos 5, the message reads:
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8080On Claude Sonnet 5.5, `thinking: {type: "disabled"}` returns a 400 error at every effort level. The message reads:
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8282```text wrap
83"thinking.type.disabled" is not supported for this model. Use "thinking.type.between_tools" for the lowest thinking setting, or "thinking.type.adaptive" and "output_config.effort" to control thinking behavior.
83To turn thinking off on this model, send "thinking": {"type": "between_tools"} instead of {"type": "disabled"}. The model does not think before responding. The short updates it writes between tool calls come back as thinking blocks.
8484```
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8686To turn off up-front thinking on Claude Sonnet 5.5, send `thinking: {type: "between_tools"}` instead, at effort `high` or below.
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