openclaw - 💡(How to fix) Fix Feature: Proactive auto-compaction with chained summaries [1 participants]

Summary

Automatically compact session history when approaching context limits, using a summary-chaining strategy that preserves deep context across multiple compactions.

Motivation

Currently, sessions hit context limits unexpectedly, requiring manual /compact. Claude Code's architecture reveals a robust multi-strategy approach:

1. Proactive compaction at ~85% context capacity (before it's a problem)
2. Reactive compaction on prompt_too_long API errors (emergency recovery)
3. Summary chaining — when compacting a session that was already compacted, the old summary is preserved alongside the new one

The summary chaining is the key insight. Without it, each compaction destroys context from previous compactions. With it, you get layered summaries:

- Previously compacted context:
  - Scope: 15 earlier messages compacted
  - Tools mentioned: exec, read, edit
  - Key files: src/main.ts, config.yaml
- Newly compacted context:
  - Scope: 8 messages compacted  
  - Recent user requests: [...]
  - Current work: [...]

Proposed Behavior

Proactive Compaction

• Track estimated token usage per session
• At 85% capacity: log a warning
• At 90% capacity: auto-trigger compaction
• Preserve last N messages verbatim (configurable, default 4-6)
• Generate structured summary of older messages

Reactive Compaction

• On prompt_too_long API error: compact and retry (once)
• If compact + retry fails: surface error to user with context

Summary Chaining

When compacting a session that already has a compacted summary:

1. Extract the existing summary
2. Generate new summary from messages since last compaction
3. Merge: Previously compacted context + Newly compacted context
4. Include continuation instruction: "Resume directly — do not acknowledge the summary"

Structured Summary Extraction

Summaries should include:

• Scope (message counts by role)
• Tools mentioned
• Recent user requests (last 3)
• Pending/incomplete work items
• Key files referenced
• Current work state

Configuration

compaction:
  auto: true
  warningThreshold: 0.85
  compactThreshold: 0.90
  preserveRecentMessages: 6
  chainSummaries: true

Prior Art

• Claude Code: src/services/compact/autoCompact.ts, reactiveCompact.ts
• Claw Code (Rust): rust/crates/runtime/src/compact.rs — clean implementation of summary chaining with merge_compact_summaries()