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Sweep 22 Oct 2026 · 04:32Z Build v2.1.308 527 read Stable v2.1.308 Latest v2.1.308 Next v2.1.308 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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context-editing changedbuild-with-claude/context-editing

Nearest release: v2.1.293, 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 edits18to this page, all time

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5050 | ---------------- | --------------------------- | ------------------------------------------ |
5151 | Opus | Claude Opus 4.5 and later | Claude Opus 4.1 and earlier |
5252 | Sonnet | Claude Sonnet 4.6 and later | Claude Sonnet 4.5 (deprecated) and earlier |
53 | Haiku | (none) | All models through Claude Haiku 4.5 |
53 | Haiku | Claude Haiku 5.5 and later | Claude Haiku 4.5 and earlier |
5454 | Fable and Mythos | All models | (none) |
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5656 Use this strategy to override the default. If your code runs across multiple model tiers, set `keep` explicitly rather than relying on the per-model default.
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6363Context 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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65On Claude Fable 5.1, Claude Opus 5.5, and Claude Sonnet 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. For new accounts created on or after August 31, 2026, a request that replays an invalidated block is rejected unless you opt into dropping it. See [Keeping the prefix unchanged](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking#prefix-check).
65On Claude Fable 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. For new accounts created on or after August 31, 2026, a request that replays an invalidated block is rejected unless you opt into dropping it. See [Keeping the prefix unchanged](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking#prefix-check).
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6767### Context editing and prompt caching
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922922The `clear_thinking_20251015` strategy supports the following configuration:
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924| Configuration option | Default | Description |
925| -------------------- | -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
926| `keep` | Model-specific | Defines how many recent assistant turns with thinking blocks to preserve. Use `{type: "thinking_turns", value: N}` where N must be > 0 to keep the last N turns, or `"all"` to keep all thinking blocks. Opus 4.5+ and Sonnet 4.6+: all turns. Fable and Mythos models: all turns. Earlier Opus/Sonnet and all Haiku: last turn only. |
924| Configuration option | Default | Description |
925| -------------------- | -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
926| `keep` | Model-specific | Defines how many recent assistant turns with thinking blocks to preserve. Use `{type: "thinking_turns", value: N}` where N must be > 0 to keep the last N turns, or `"all"` to keep all thinking blocks. Opus 4.5+, Sonnet 4.6+, and Haiku 5.5+: all turns. Fable and Mythos models: all turns. Earlier Opus/Sonnet and Haiku through Claude Haiku 4.5: last turn only. |
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928928**Example configurations:**
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