What this read moved
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build-with-claude/compaction Changed · +1 / -1 lines
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34183418Compacting this way gives you three things. First, you decide when to compact. Second, the summarization request can run in the background while the conversation continues on its full history, and you swap the block in when it arrives. This is often called async or background compaction. Third, you can keep recent turns word for word after the summary, which is often called keep-tail compaction. Models with [preserved thinking](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking) check earlier thinking blocks against the conversation. On those models, the thinking in turns that follow the summary, from either pattern, can stay valid after the swap, under the conditions in [Continue from the summary](https://platform.claude.com/docs/en/build-with-claude/compaction#continue-from-the-summary). That lets a long-running agent keep its train of thought. Use threshold compaction when you want the API to manage context inside ordinary requests. Use the `compaction` parameter when your application needs to control when compaction happens, can't pause while a summary is written, or must keep recent turns and their thinking after the summary.
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3420Send the `compact-2026-09-04` beta header on the request that asks for the summary and on every later request that carries the signed block. On-demand compaction is available on the Claude API only, on Claude Fable 5.1, Claude Mythos 5.1, Claude Fable 5, Claude Mythos 5, Claude Mythos Preview, Claude Opus 5, Claude Opus 4.8, Claude Opus 4.7, Claude Opus 4.6, Claude Sonnet 5, and Claude Sonnet 4.6. You can also call the [Models API](https://platform.claude.com/docs/en/api/beta/models/list) with the beta header and read each model's `capabilities.compaction`. You can't combine `compaction` with `context_management` on one request.
3420Send the `compact-2026-09-04` beta header on the request that asks for the summary and on every later request that carries the signed block. On-demand compaction is available on the Claude API but not on Amazon Bedrock or Google Cloud. It works on Claude Fable 5.1, Claude Mythos 5.1, Claude Fable 5, Claude Mythos 5, Claude Mythos Preview, Claude Opus 5, Claude Opus 4.8, Claude Opus 4.7, Claude Opus 4.6, Claude Sonnet 5, and Claude Sonnet 4.6. You can also call the [Models API](https://platform.claude.com/docs/en/api/beta/models/list) with the beta header and read each model's `capabilities.compaction`. You can't combine `compaction` with `context_management` on one request.
34213421
34223422### Request a summary
34233423
build-with-claude/preserved-thinking Changed · +1 / -1 lines
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942942Another common prefix edit is client-side trimming: dropping or summarizing the oldest turns and keeping the recent ones verbatim. The kept turns' thinking blocks were produced while the removed history was still in place, so they fail the check. The server-side equivalents don't count as edits, because the check compares the conversation as you sent it:
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944* [Compaction](https://platform.claude.com/docs/en/build-with-claude/compaction) summarizes older turns into a compaction block when the context approaches a threshold you set, and the checked prefix restarts from that block. Its [`instructions` parameter](https://platform.claude.com/docs/en/build-with-claude/compaction#custom-summarization-instructions) takes your own summarization prompt, such as "preserve every ticker, position size, and stated assumption". [On-demand compaction](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking#background-compaction) (beta) returns the summary from a separate request, which can [run in the background](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking#background-compaction). Send `"compaction": {"type": "summarize"}` in the request body, and the response carries a single `compaction` block, holding the summary and a signature, instead of a reply. On-demand compaction is available on the Claude API but not on Amazon Bedrock or Google Cloud, and it needs the `compact-2026-09-04` beta header on the summary request and on every later request that carries the block. You send the block in place of the messages it summarizes. The check accepts that swap, so the turns you keep can stay valid with their thinking, under the conditions in [Keep-tail compaction](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking#keep-tail-compaction).
944* [Compaction](https://platform.claude.com/docs/en/build-with-claude/compaction) summarizes older turns into a compaction block when the context approaches a threshold you set, and the checked prefix restarts from that block. Its [`instructions` parameter](https://platform.claude.com/docs/en/build-with-claude/compaction#custom-summarization-instructions) takes your own summarization prompt, such as "preserve every ticker, position size, and stated assumption". [On-demand compaction](https://platform.claude.com/docs/en/build-with-claude/compaction#compact-on-demand-with-the-compaction-parameter) (beta) returns the summary from a separate request, which can [run in the background](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking#background-compaction). Send `"compaction": {"type": "summarize"}` in the request body, and the response carries a single `compaction` block, holding the summary and a signature, instead of a reply. On-demand compaction is available on the Claude API but not on Amazon Bedrock or Google Cloud, and it needs the `compact-2026-09-04` beta header on the summary request and on every later request that carries the block. You send the block in place of the messages it summarizes. The check accepts that swap, so the turns you keep can stay valid with their thinking, under the conditions in [Keep-tail compaction](https://platform.claude.com/docs/en/build-with-claude/preserved-thinking#keep-tail-compaction).
945945* [Context editing](https://platform.claude.com/docs/en/build-with-claude/context-editing) clears old tool results or old thinking blocks by rule, oldest first. The strategies are `clear_tool_uses_20250919` and `clear_thinking_20251015`.
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947947### Compact on the client
cli-sdks-libraries/cli/quickstart Changed · +1 / -1 lines
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2929 For Linux environments, download the release binary directly.
3030
3131 ```bash
32 VERSION=1.30.0
32 VERSION=1.33.0
3333 OS=$(uname -s | tr '[:upper:]' '[:lower:]')
3434 case $(uname -m) in
3535 x86_64) ARCH=amd64 ;;
get-started Changed · +1 / -1 lines
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77## Prerequisites
88
99* A [Claude Console account](https://platform.claude.com)
10* An [API key](https://platform.claude.com/settings/keys)
10* An [API key](https://platform.claude.com/docs/en/get-api-key)
1111
1212## Call the API
1313
manage-claude/cmek Changed · +1 / -1 lines
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106106**Claude Enterprise**
107107
108108* Beta and research preview features might not be covered by CMEK and can break in CMEK organizations, for example, Claude Security and Claude Design.
109* [Personal preferences - Instructions for Claude section](https://claude.ai/new#settings/general) and Cowork Global instructions. These are set at the account level and shared across all of a user's organizations.
109* [Personal preferences - Instructions for Claude section](https://claude.ai/new#settings/account) and Cowork Global instructions. These are set at the account level and shared across all of a user's organizations.
110110
111111On both products, account data for users in your organization (such as names, email addresses, and profile pictures) is not encrypted under your key.
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release-notes/overview Changed · +1 / -1 lines
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1919### September 10, 2026
2020
2121* Claude Managed Agents permission policies now include `auto`: the server evaluates each agent or MCP tool call and runs it, denies it, or pauses for your approval. `agent.tool_use` and `agent.mcp_tool_use` events report how each call was evaluated in an `evaluation` field alongside `evaluated_permission`. See [Let the server evaluate each call with `auto`](https://platform.claude.com/docs/en/managed-agents/permission-policies#let-the-server-evaluate-each-call-with-auto).
22* The `ant` CLI adds `ant beta:sessions connect`, which attaches your terminal to a Claude Managed Agents session. You can follow the session live, send messages, and allow or deny tool calls that are waiting for approval. Pass `--web` to serve the Claude Console's session viewer locally and open the session there instead. See [Connect to a Managed Agents session from your terminal](https://platform.claude.com/docs/en/cli-sdks-libraries/cli/sessions-connect).
22* Version 1.32.0 of the `ant` CLI adds `ant beta:sessions connect`, which attaches your terminal to a Claude Managed Agents session. You can follow the session live, send messages, and allow or deny tool calls that are waiting for approval. Pass `--web` to serve the Claude Console's session viewer locally and open the session there instead. See [Connect to a Managed Agents session from your terminal](https://platform.claude.com/docs/en/cli-sdks-libraries/cli/sessions-connect).
2323
2424### September 3, 2026
2525