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Sweep 22 Oct 2026 · 21:04Z Build v2.1.309 528 read Stable v2.1.308 Latest v2.1.309 Next v2.1.309 Feeds RSS JSON llms.txt llms-full.txt Unofficial
HomeDocsClaude Developer Platform 22 Oct 2026
One change · api

Message Batches API changedbuild-with-claude/batch-processing

Nearest release: v2.1.309, published an hour before 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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First seen 14 Aug 2026 this site's first read of the page
Recorded edits25to this page, all time

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15511551The `output-300k-2026-03-24` beta header raises the `max_tokens` cap to 300,000 for batch requests using Claude Opus 5.5, Claude Opus 5, Claude Opus 4.8, Claude Opus 4.7, Claude Opus 4.6, Claude Sonnet 5.5, Claude Sonnet 5, Claude Sonnet 4.6, or Claude Haiku 5.5. Include the header to generate outputs far longer than the standard 128k `max_tokens` limit in a single turn.
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15531553<Note>
1554 Extended output is available on the Message Batches API only, not the synchronous Messages API. It is supported on the Claude API and Claude Platform on AWS, and is not currently available on Amazon Bedrock, Google Cloud, or Microsoft Foundry.
1554 Extended output is available on the Message Batches API only, not the synchronous Messages API. It is supported on the Claude API and Claude Platform on AWS, and is not currently available on Amazon Bedrock, Claude Models on Google Cloud (Google managed), or Microsoft Foundry.
15551555</Note>
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15571557Use extended output for long-form generation such as book-length drafts and technical documentation, exhaustive structured data extraction, large code-generation scaffolds, and long reasoning chains.
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