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Sweep 09 Oct 2026 · 17:27Z Build v2.1.296 517 read Stable v2.1.287 Latest v2.1.296 Next v2.1.296 Feeds RSS JSON llms.txt llms-full.txt Unofficial
HomeDocsClaude Developer Platform 8 Oct 2026
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errors changedapi/errors

Nearest release: v2.1.294, published an hour after this site recorded the change. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.

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From line 505 where the diff opens
First seen 14 Aug 2026 this site's first read of the page
Recorded edits16to this page, all time

The whole hunk

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505505messages.N: output_config.effort 'low' differs from the 'high' in effect before it; effort cannot change when thinking is disabled on this model. Use effort 'high', or enable thinking.
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508Claude Haiku 5.5 accepts `thinking: {"type": "disabled"}` and holds it to the same two effort limits that apply to `between_tools`: at `xhigh` or `max` effort, or with a per-message `output_config.effort` that differs from the level in effect, the request returns a 400 `invalid_request_error` with the matching message above.
508Claude Haiku 5.5 accepts `thinking: {"type": "disabled"}` and holds it to the same two effort limits that apply to `between_tools`: at `xhigh` or `max` effort, or with a per-message `output_config.effort` that differs from the level in effect, the request returns a 400 `invalid_request_error` with the matching message shown earlier.
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510510In both messages, "enable thinking" means adaptive thinking: omit the `thinking` field or send `thinking: {"type": "adaptive"}`. Claude Sonnet 5.5 rejects `"enabled"` with a 400 error. To vary effort per turn, use adaptive thinking.
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