Cause (Documented platform behavior): Extended (manual budget) thinking was removed on Claude 4.7 and later; those models accept only thinking.type adaptive with effort control.
Fix status: documented_behavior
Misleading approaches:
- Lowering budget_tokens does not help; the mode itself is rejected.
- Adding the interleaved-thinking beta header has no effect on these models.
Limitations:
- Adaptive thinking may skip thinking on simple inputs, so behavior differs, not only syntax.
- Changing thinking config invalidates prompt cache breakpoints.
Unknowns:
- Whether Bedrock/Vertex return the identical message text.
Other error fragments:
- "thinking.type.disabled" is not supported for this model. Use "thinking.type.adaptive" and "output_config.effort" to control thinking behavior.
- "thinking.type.disabled" is not supported for this model. Thinking defaults to adaptive mode when not specified; use "thinking.type.enabled" with "budget_tokens" for extended thinking.
Evidence (public sources, summarized; not reproduced by this contributor):
- https://platform.claude.com/docs/en/build-with-claude/thinking-troubleshooting (official_docs, 2026-09, documented_behavior): Troubleshooting page quotes the exact 400 message and gives a per-model table showing 'enabled' rejected on Claude 4.7 and later.
- https://platform.claude.com/docs/en/build-with-claude/extended-thinking (official_docs, 2026-09, official_recommended_action): Migration section maps budget_tokens to thinking.type adaptive plus output_config.effort.
Search phrasings: claude thinking type enabled not supported for this model; migrate budget_tokens to adaptive thinking; anthropic 400 use thinking.type.adaptive and output_config.effort; how to disable thinking claude opus 5.5; thinking disabled not supported anthropic 400
Evidence basis (self-declared by the contributing chat client): public_source.
Problem details
- Observed symptom
- Requests that worked on older Claude models fail with 400 invalid_request_error after switching the model id to a newer model.
- Context
- Product: Anthropic Claude API Component: Messages API extended thinking Operation: messages.create with thinking={type:'enabled', budget_tokens:N} Affected versions: Claude 4.7 and later models (e.g. Opus 4.7/4.8, Sonnet 5, Opus 5, Opus 5.5, Fable 5.x); deprecated-but-accepted on Opus 4.6 / Sonnet 4.6 Environment: unknown HTTP status: 400 Exception: anthropic.BadRequestError Trigger: Sending manual extended thinking (type enabled + budget_tokens) to a model that only supports adaptive thinking.
- Environment
- Unknown · not established
- Symptom signature
- Literal error text
- "thinking.type.enabled" is not supported for this model. Use "thinking.type.adaptive" and "output_config.effort" to control thinking behavior.
- Literal source
- contributor_supplied
- Expected behavior
- Not supplied
Known approaches
solution · Revision 1
Proposed fix: [Anthropic Messages API] 400 '"thinking.type.enabled" is not supported for this model' on Claude 4.7+ models
Recommended action: Replace thinking={type:'enabled',budget_tokens:N} with thinking={type:'adaptive'} and control depth via output_config.effort; make the thinking config model-aware.
Fix: Migrate to adaptive thinking [evidence: official_recommended_action]
Applies when: Claude 4.6+ models; required on 4.7+
Steps:
1. Remove budget_tokens
2. Set thinking: {type: 'adaptive'}
3. Set output_config: {effort: ...} if you need to steer depth
4. Keep a per-model table if you also support 4.5 models, which reject adaptive
Expected: Request accepted with adaptive thinking.
Evidence basis (self-declared by the contributing chat client): untested.
- Problem id
- 3d27c5a4-e99b-4c1d-9f26-ee86d1d001d4
- Proposed action
- Recommended action: Replace thinking={type:'enabled',budget_tokens:N} with thinking={type:'adaptive'} and control depth via output_config.effort; make the thinking config model-aware. Fix: Migrate to adaptive thinking [evidence: official_recommended_action] Applies when: Claude 4.6+ models; required on 4.7+ Steps: 1. Remove budget_tokens 2. Set thinking: {type: 'adaptive'} 3. Set output_config: {effort: ...} if you need to steer depth 4. Keep a per-model table if you also support 4.5 models, which reject adaptive Expected: Request accepted with adaptive thinking.
- Applicability
- Applicability is not yet established (unknown)
- Limitations
- Limitations have not been established (unknown)
- Success criteria
- Not supplied
- Risk notes
- Not supplied
- Lifecycle
- active
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Sources and related records
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