/compact-guard

name: compact-guard
description: Smart context compaction with state preservation. Saves critical files, task progress, and working state before compaction, restores after. Use before manual compact or when auto-compact triggers.
user-invocable: true

Compact Guard

Protect important context through compaction cycles. Based on Claude Code internals: compaction restores max 5 files with 5K tokens each, within a 50K total budget.

Trigger

Use before `/compact` or when auto-compact warning appears.

Key Constants (from Claude Code source)

• `POST_COMPACT_MAX_FILES_TO_RESTORE = 5` — only 5 files survive
• `POST_COMPACT_TOKEN_BUDGET = 50K` — total restore budget
• `POST_COMPACT_MAX_TOKENS_PER_FILE = 5K` — per-file limit
• Auto-compact fires at `context_window - 13K` buffer

Pre-Compact Checklist

Before compacting, save these to memory or a scratch file:

1. **Current task** — What are you working on? One sentence. 2. **Files in progress** — Which files are being edited? (max 5 — compaction only restores 5) 3. **Decisions made** — Any architectural choices made this session 4. **Blockers** — What's preventing progress? 5. **Next steps** — What to do immediately after compact

Strategy: Microcompact First

Before full compaction, try microcompact:

• Large tool results (test output, grep results) can be trimmed
• File reads that are no longer relevant can be dropped
• Use subagents for heavy exploration to keep main context clean

Post-Compact Recovery

After compaction, immediately:

1. Re-read the top-priority file (the one you're actively editing) 2. Check task list for current progress 3. Review any scratch notes saved pre-compact 4. Resume from next steps

Prevention Strategies

| Strategy | Token Savings | When | |----------|--------------|------| | Delegate grep/search to subagent | 30-60% per search | Always for broad searches | | Read only needed lines (`offset`/`limit`) | 50-90% per read | Large files | | Compact at task boundaries | Preserves coherence | Between logical steps | | Use `/resume` for fresh start | 100% | Unrelated new task |

Output

After running compact-guard:

COMPACT GUARD
  Files to preserve: [list top 5]
  Task state: [one sentence]
  Decisions: [key choices]
  Next step: [immediate action after compact]

  Ready to compact. Run /compact now.

Rules

• Always save state before compacting — never compact blind
• Prioritize the file you're actively editing as #1 to restore
• If auto-compact fires unexpectedly, immediately re-read your working file
• Keep CLAUDE.md under 60 lines to leave room for actual context