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Context Window & Compaction

Every model has a context window (max tokens it can see). Long-running chats accumulate messages and tool results; once the window is tight, OpenClaw compacts older history to stay within limits.

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What compaction is

Compaction summarizes older conversation into a compact summary entry and keeps recent messages intact. The summary is stored in the session history, so future requests use:
  • The compaction summary
  • Recent messages after the compaction point
Compaction persists in the session’s JSONL history.

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Configuration

Use the agents.defaults.compaction setting in your openclaw.json to configure compaction behavior (mode, target tokens, etc.). Compaction summarization preserves opaque identifiers by default (identifierPolicy: "strict"). You can override this with identifierPolicy: "off" or provide custom text with identifierPolicy: "custom" and identifierInstructions.

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Auto-compaction (default on)

When a session nears or exceeds the model’s context window, OpenClaw triggers auto-compaction and may retry the original request using the compacted context. You’ll see:
  • 🧹 Auto-compaction complete in verbose mode
  • /status showing 🧹 Compactions: <count>
Before compaction, OpenClaw can run a silent memory flush turn to store durable notes to disk. See Memory for details and config.

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Manual compaction

Use /compact (optionally with instructions) to force a compaction pass: 
/compact Focus on decisions and open questions

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Context window source

Context window is model-specific. OpenClaw uses the model definition from the configured provider catalog to determine limits.

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Compaction vs pruning

  • Compaction: summarises and persists in JSONL.
  • Session pruning: trims old tool results only, in-memory, per request.
See /concepts/session-pruning for pruning details.

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OpenAI server-side compaction

OpenClaw also supports OpenAI Responses server-side compaction hints for compatible direct OpenAI models. This is separate from local OpenClaw compaction and can run alongside it.
  • Local compaction: OpenClaw summarizes and persists into session JSONL.
  • Server-side compaction: OpenAI compacts context on the provider side when store + context_management are enabled.
See OpenAI provider for model params and overrides.

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Tips

  • Use /compact when sessions feel stale or context is bloated.
  • Large tool outputs are already truncated; pruning can further reduce tool-result buildup.
  • If you need a fresh slate, /new or /reset starts a new session id.