openclaw - 💡(How to fix) Fix feat(hooks): include compaction summary text in after_compaction hook payload [1 participants]

Problem

The after_compaction hook event currently provides basic metadata (session key, message counts) but does not include the actual compaction summary text that was generated.

Plugins that want to audit compaction quality, score signal preservation, or extract key facts from the summary have no way to access this data. The summary is injected inline into the next user message as <summary>...\</summary> context, but is not persisted as a separate tagged message in the session JSONL or passed through the hook.

Use Case

A compact-review plugin that:

1. Scores signal preservation (did the summary retain infrastructure facts, active assignments, recent decisions?)
2. Writes a recovery checkpoint to daily notes before context is lost
3. Alerts when critical facts appear to be dropped

Currently requires parsing the inline <summary> tags from subsequent user messages in the JSONL — fragile and unreliable.

Proposed Change

Extend PluginHookAfterCompactionEvent to include the summary text:

export type PluginHookAfterCompactionEvent = {
  sessionKey: string;
  agentId?: string;
  messagesRetained: number;
  messagesDropped: number;
  /** The compaction summary text that was generated, if available */
  summaryText?: string;
  /** Tokens in the summary */
  summaryTokens?: number;
};

This is a non-breaking addition (optional field). Plugins that don't need it are unaffected.

Why This Matters

Compaction is a lossy operation. Plugins need visibility into what the summary actually contains to:

• Verify critical context (open assignments, infrastructure state) was preserved
• Write supplemental memory to daily notes before the session window slides
• Alert when important facts are dropped

Without this, the after_compaction hook is limited to recording that compaction occurred, not whether it was faithful.

Notes

• The summary text is already being generated and injected into context — this is just about surfacing it to plugins
• Could also expose pre-compaction message content for more sophisticated scoring