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Sweep 27 Oct 2026 · 19:04Z Build v2.1.312 531 read Stable v2.1.308 Latest v2.1.312 Next v2.1.312 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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compaction-keep-recent-turns changedbuild-with-claude/compaction-keep-recent-turns

Nearest release: v2.1.312, published under 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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From line 491 where the diff opens
First seen 21 Sep 2026 this site's first read of the page
Recorded edits9to this page, all time

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491491* **Picking the cut:** The program keeps the last two turns, where a turn is one `user` message and the reply to it. It splits the history four messages from the end, so the kept turns start with a `user` message.
492492* **Deciding when to compact:** The size check also requires that the conversation has more turns than the program keeps, so the older part is never empty.
493493* **The compaction request:** Where the loop sends the whole history, this version sends only the older messages.
494* **The swap:** Where the loop replaces the whole history with the returned message, this version's new history is the returned message followed by the kept turns.
494* **The swap:** Where the loop replaces the whole history with the returned message, this version’s new history is the returned message followed by the kept turns.
495495 
496496The `stop_reason` check and every request after the swap are unchanged from the loop.
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500500If you send thinking blocks back on a model with [preserved thinking](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking), the thinking in the kept turns stays valid only while the [conditions for kept thinking](https://platform.claude.com/docs/en/build-with-claude/compaction-thinking-blocks#conditions-for-kept-thinking-to-stay-valid) hold, and one of them limits where the cut can fall.
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502The program's cut, between a reply and the next `user` message, meets that condition. So does a cut at the end of a request you already made: compact exactly that request's `messages`, and keep everything your history has gained since.
502The program’s cut, between a reply and the next `user` message, meets that condition. So does a cut at the end of a request you already made: compact exactly that request’s `messages`, and keep everything your history has gained since.
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