# Context Compactor

> Analyzes and compacts context-affecting documents (project memory, CLAUDE.md, skill files) to reduce token usage and compaction frequency. Manual trigger only. Always requires user approval before making changes.

- Skill: `fubira/context-compactor` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add fubira/context-compactor`
- Raw SKILL.md: https://api.skillmd.com/api/skills/fubira/context-compactor/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: fubira (https://skillmd.com/u/fubira)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/fubira/context-compactor

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# Context Compactor Skill

Analyze and compact documents that affect context window size. Reduce token usage while preserving essential information.

## Activation Triggers

**Manual only** — never auto-activate.

- `/compact-context` — run full analysis
- "コンテキストを整理して", "compact context", "reduce context size"

## Target Files

| Target | Path Pattern | Description |
|--------|-------------|-------------|
| Project Memory | `.claude/projects/*/memory/*.md` | Auto-memory files that grow over time |
| Project CLAUDE.md | `{project}/CLAUDE.md` | Project-specific instructions |
| Global CLAUDE.md | `~/.claude/CLAUDE.md` | Global instructions |
| Skill files | `~/.claude/skills/*/SKILL.md` | Skill definitions |

## Workflow

### Phase 1: Measure

Run `~/.claude/scripts/context-audit.sh` to get a per-file size inventory (CLAUDE.md, per-project MEMORY.md and topic files, each SKILL.md with its frontmatter description size). The script reports raw line/char counts only — for actual context usage, check the built-in `/context` command. Identify the largest contributors from the output.

### Phase 2: Analyze

For each target file, detect:

- **Redundancy**: Content duplicated across files (e.g., CLAUDE.md vs skills, memory vs CLAUDE.md)
- **Obsolescence**: Outdated information (completed tasks, old decisions, superseded patterns)
- **Verbosity**: Content that can be expressed more concisely without losing meaning
- **Language inefficiency**: Japanese text in technical/process docs where English would use fewer tokens

### Phase 3: Propose

Present findings as a structured table:

```markdown
| File | Current | Est. After | Reduction | Changes |
|------|---------|-----------|-----------|---------|
| ... | ... | ... | ... | Brief description |
```

For each file with proposed changes, show:
- What will be removed/compacted (with reasoning)
- What will be preserved (and why)

**Wait for user approval before proceeding.**

### Phase 4: Execute (after approval)

- Apply approved changes only
- Show before/after line counts
- Suggest committing if in a git repo

## Analysis Rules

Classification rules (MUST preserve / Safe to compact / Requires user judgment) are in `references/rules.md`. Read it before Phase 2 (Analyze).

## Important Notes

- Never delete without showing what will be removed
- Preserve meaning even when reducing words
- When in doubt, keep — false deletion is worse than slight verbosity
- This skill does NOT auto-activate — context growth is normal and expected