Long Claude Code sessions eventually hit a context wall. Claude Code then spends a long turn compacting history — you wait. Power Claude’s Warm Compacting pre-builds that summary in the background so when the wall arrives, the expensive wait is already done.
TL;DR
| Question | Answer |
|---|---|
| What is it? | Pre-build of the compaction summary before Claude Code autocompacts |
| Default | On (powerClaude.warmCompacting.enabled) |
| What you feel | Fewer multi-minute “stuck compacting” pauses on long jobs |
| Risk knobs | Token caps, fire %, apply-rewrite gate |
| Not | Bypassing model limits or Anthropic rate limits |
Why compacting hurts
Claude Code’s conversation grows with tool output, diffs, and plans. Near the model window, the product compacts older turns into a shorter summary. That compact turn is useful — and slow. Heavy agent fleets hit it mid-sprint.
Warm Compacting watches proximity to the compact threshold (configurable percent of the window), builds an abstractive summary of the earlier conversation before you’re blocked, and can inject it when the real compact would fire.
How to enable (VS Code)
- Install Power Claude.
- Open Settings → search
warmCompacting. - Confirm Warm Compacting: Enabled is on (default).
- Optional: set
tokenSaver.level/ Token Saver so less junk enters the window in the first place. - Run a long session; watch Debug / events for warm-compact activity if you need proof.
Settings that matter
| Setting | Role |
|---|---|
powerClaude.warmCompacting.enabled | Master switch |
…autocompactPercentOfWindow | Where “the wall” is estimated (default ~90%) |
…triggerPercentOfCompactThreshold | When to start pre-build (default ~80% of that wall) |
…maxWarmSummaryTokens | Cap size of the warm summary |
…applyRewrite | Whether to actually splice the warm compact live |
…maxWarmCompactsPerSession | Efficiency cap (default 1) |
Exact ranges: Power Claude Settings catalogue / docs/system-index.md in the extension repo.
When to leave it on
- Overnight or multi-hour agent loops
- Sub-agent fan-out that floods tool output
- Any workflow where a random 2–5 minute compact kills flow
When to tune or disable
- You need maximum fidelity of early-session detail (raise summary token cap carefully, or disable apply-rewrite and observe).
- You’re debugging compact behavior itself — use shadow-style caution and Debug tab.
- Emergency: global kill switch
~/.power-claude/state/emergency-off.
Pair with Token Saver
Warm Compacting reduces wait. Token Saver reduces how fast you race toward the wall. Together they compound: less junk in context + less stall when compacting.
FAQ
Does this violate Anthropic terms?
No. It works with local session context and official Claude Code behavior. It does not invent extra Anthropic quota.
Is the summary lossy?
Yes — compaction is always lossy. Warm Compacting’s job is timing and continuity, not perfect archival. Critical facts still belong in files/tests, not only chat memory.
How do I know it fired?
Dashboard events / Debug diagnostics; long sessions that previously froze at the wall should continue with a short warm path instead of a full stall.
Related features
Primary sources
- Power Claude system index: Warm Compacting settings
- Video storyboard:
media/video/scenes/warm-compacting/in the extension repo - Product: neural-llm.com/power-claude
Independent third-party software by Neural-LLM. Not affiliated with Anthropic.