Strategic Compact Skill

Suggests manual /compact at strategic points in your workflow rather than relying on arbitrary auto-compaction.

When to Activate

• Running long sessions that approach context limits (200K+ tokens)
• Working on multi-phase tasks (research → plan → implement → test)
• Switching between unrelated tasks within the same session
• After completing a major milestone and starting new work
• When responses slow down or become less coherent (context pressure)

Why Strategic Compaction?

Auto-compaction triggers at arbitrary points:

• Often mid-task, losing important context
• No awareness of logical task boundaries
• Can interrupt complex multi-step operations

Strategic compaction at logical boundaries:

• After exploration, before execution — Compact research context, keep implementation plan
• After completing a milestone — Fresh start for next phase
• Before major context shifts — Clear exploration context before different task

How It Works

The suggest-compact.js hook runs on Stop events and:

1. Tracks message count — Increments a counter in session state on each stop
2. Threshold detection — Suggests compaction at a configurable threshold (default: 50 messages)
3. Periodic reminders — Reminds every 25 messages after threshold

The hook outputs suggestions to stderr so they appear as non-blocking notices.

Compaction Decision Guide

Use this table to decide when to compact:

Phase Transition	Compact?	Why
Research → Planning	Yes	Research context is bulky; plan is the distilled output
Planning → Implementation	Yes	Plan is in TodoWrite or a file; free up context for code
Implementation → Testing	Maybe	Keep if tests reference recent code; compact if switching focus
Debugging → Next feature	Yes	Debug traces pollute context for unrelated work
Mid-implementation	No	Losing variable names, file paths, and partial state is costly
After a failed approach	Yes	Clear the dead-end reasoning before trying a new approach

What Survives Compaction

Understanding what persists helps you compact with confidence:

Persists	Lost
CLAUDE.md instructions	Intermediate reasoning and analysis
TodoWrite task list	File contents you previously read
Files on disk (instincts, state)	Multi-step conversation context
Git state (commits, branches)	Tool call history and counts
Skill definitions	Nuanced user preferences stated verbally

Best Practices

1. Compact after planning — Once plan is finalized in TodoWrite, compact to start fresh
2. Compact after debugging — Clear error-resolution context before continuing
3. Don't compact mid-implementation — Preserve context for related changes
4. Read the suggestion — The hook tells you when, you decide if
5. Write before compacting — Save important context to files or memory before compacting
6. Use /compact with a summary — Add a custom message: /compact Focus on implementing auth middleware next

Token Optimization Patterns

Context Composition Awareness

Monitor what's consuming your context window:

• CLAUDE.md files — Always loaded, keep lean
• Loaded skills — Each skill adds 1-5K tokens
• Conversation history — Grows with each exchange
• Tool results — File reads, search results add bulk

Duplicate Instruction Detection

Common sources of duplicate context:

• Same rules in both global and project CLAUDE.md
• Skills that repeat CLAUDE.md instructions
• Multiple skills covering overlapping domains

Configuration

Environment variables:

• COMPACT_THRESHOLD — Messages before first suggestion (default: 50)