context-editing changedbuild-with-claude/context-editing
Nearest release: v2.1.321, 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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First seen
14 Aug 2026
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Recorded edits28to this page, all time
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99 eligibility: eligible
1010 note: Excludes [Covered Models](https://platform.claude.com/docs/en/manage-claude/api-and-data-retention#model-specific-data-retention-requirements). Context edits (tool use clearing and thinking clearing) are applied in real time.
1111 supportedModels:
12 - claude-fable-5-2
13 - claude-mythos-5-2
1214 - claude-fable-5-1
1315 - claude-mythos-5-1
1416 - claude-fable-5
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9092Context editing is applied server-side before the prompt reaches Claude. Your client application maintains the full, unmodified conversation history. You do not need to sync your client state with the edited version. Continue managing your full conversation history locally as you normally would.
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92On Claude 5.1 and later models, server-side context management never invalidates thinking blocks. Client-side edits to earlier turns can invalidate the thinking blocks in every later assistant turn. See [Keeping the prefix unchanged](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking#prefix-check).
94On Claude Fable 5.2, Claude Mythos 5.2, Claude Fable 5.1, Claude Mythos 5.1, Claude Opus 5.5, Claude Sonnet 5.5, and Claude Haiku 5.5, server-side context management never invalidates thinking blocks. Client-side edits to earlier turns can invalidate the thinking blocks in every later assistant turn. See [Keeping the prefix unchanged](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking#prefix-check).
9395
9496### Context editing and prompt caching
9597
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