Compact Guard Skill for Claude

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:

• Current task — What are you working on? One sentence.
• Files in progress — Which files are being edited? (max 5 — compaction only restores 5)
• Decisions made — Any architectural choices made this session
• Blockers — What's preventing progress?
• 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:

• Re-read the top-priority file (the one you're actively editing)
• Check task list for current progress
• Review any scratch notes saved pre-compact
• 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