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Sweep 02 Oct 2026 · 18:55Z Build v2.1.288 509 read Stable v2.1.285 Latest v2.1.288 Next v2.1.288 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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compaction-background changedbuild-with-claude/compaction-background

Nearest release: v2.1.285, published 2 hours 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 21 Sep 2026 this site's first read of the page
Recorded edits6to this page, all time

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4141For example, if the compaction request held messages 1 to 5 and the conversation gained messages 6 to 8 while it ran, after the swap your history is the block followed by messages 6 to 8.
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43![Background compaction timeline: the compaction request is sent with messages 1 to 5 while the conversation continues on its full history and gains messages 6 to 8; when the block arrives, it replaces messages 1 to 5 at the front of the history, and the history becomes the block followed by messages 6 to 8](https://platform.claude.com/docs/images/compaction-background-timeline.svg)
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44 ![Background compaction timeline: the compaction request is sent with messages 1 to 5 while the conversation continues on its full history and gains messages 6 to 8; when the block arrives, it replaces messages 1 to 5 at the front of the history, and the history becomes the block followed by messages 6 to 8](https://platform.claude.com/docs/images/compaction-background-timeline.svg)
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4547If the response has any other `stop_reason`, no summary was produced, which counts as a failure in step 2. Keep the full history; [Handle a missing summary or an error](https://platform.claude.com/docs/en/build-with-claude/compaction-on-demand#when-no-summary-comes-back) lists the causes and what to do for each.
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