checkpointing

name	checkpointing
description	Save full session context: git history, Agent Teams activity, and discover reusable skill patterns — all in one run. No flags needed. Run at session end, after major milestones, or when you want to capture learnings.
metadata	{"short-description":"Full session checkpoint with skill pattern discovery"}

Checkpointing — セッションの全記録とパターン発見

セッションの全活動を記録し、再利用可能なパターンを発見する。毎回全部やる。

What It Does (Every Time)

/checkpointing
    ↓
┌─────────────────────────────────────────────────────────────┐
│  1. Collect Everything                                       │
│     ├── git log (commits, file changes, line stats)          │
│     ├── Agent Teams activity (tasks, teammates, messages)    │
│     └── Design decisions (.claude/docs/DESIGN.md changes)    │
│                                                              │
│  2. Generate Checkpoint                                      │
│     → .claude/checkpoints/YYYY-MM-DD-HHMMSS.md              │
│                                                              │
│  3. Update Session History                                   │
│     → CLAUDE.md (cross-session persistence)                  │
│                                                              │
│  4. Discover Skill Patterns                                  │
│     → Subagent analyzes checkpoint                           │
│     → Suggests reusable skills                               │
│     → User reviews and approves                              │
└─────────────────────────────────────────────────────────────┘

Usage

# Everything. No flags needed.
/checkpointing

# Optional: only look at recent work
/checkpointing --since "2026-02-08"

What Gets Captured

Git Activity

• Commits (hash, message, date)
• File changes (created, modified, deleted + line counts)
• Branch information

Agent Teams Activity

• Team composition (Lead + Teammates, roles)
• Shared task list state (completed, in-progress, pending)
• File ownership per teammate
• Communication patterns (who messaged whom, about what)
• Team effectiveness signals (tasks completed vs stuck, file conflicts)

Teammate Work Logs

• Each Teammate's work log from .claude/logs/agent-teams/{team-name}/{teammate}.md
• Contains: Summary, Tasks Completed, Files Modified, Key Decisions, Communication with Teammates, Issues Encountered
• Written by each Teammate upon completing all assigned tasks
• Only present when Agent Teams were used (/startproject, /team-implement, /team-review)

Design Decisions

• Changes to .claude/docs/DESIGN.md since last checkpoint
• New entries in Key Decisions table

Checkpoint Format

# Checkpoint: 2026-02-08 15:30:00 UTC

## Summary

- **Commits**: 12
- **Files changed**: 15 (10 modified, 4 created, 1 deleted)
- **Agent Teams sessions**: 1 (3 teammates)
- **Tasks completed**: 8/10

## Git History

### Commits

- `abc1234` feat: redesign startproject for Opus 4.6
- `def5678` feat: add team-implement skill
  ...

### File Changes

**Created:**

- `.claude/skills/team-implement/SKILL.md` (+180)
  ...

**Modified:**

- `CLAUDE.md` (+40, -25)
  ...

## Agent Teams Activity

### Team: project-planning

**Composition:**

- Lead: Claude (orchestration)

**Task List:**

- [x] Research library options (Researcher)
- [x] Design module architecture (Architect)
- [x] Validate API constraints (Researcher)
- [x] Finalize implementation plan (Architect)

**Communication Patterns:**

- Researcher → Architect: 3 messages (library constraints)
- Architect → Researcher: 2 messages (additional research requests)

**Effectiveness:**

- All tasks completed
- No file conflicts
- 2 design iterations triggered by research findings

## Teammate Work Logs

### Team: project-planning

#### researcher

_Source: `.claude/logs/agent-teams/project-planning/researcher.md`_

# Work Log: Researcher

## Summary

Researched httpx library constraints and API patterns for the new API client module.

## Tasks Completed

- [x] Research libraries: httpx supports HTTP/2 via h2 dependency
- [x] Find documentation: httpx connection pool defaults to 100

## Communication with Teammates

- → Architect: httpx connection pool limit of 100, HTTP/2 requires h2
- ← Architect: Requested HTTP/2 multiplexing research

#### architect

_Source: `.claude/logs/agent-teams/project-planning/architect.md`_

# Work Log: Architect

## Summary

Designed API client module architecture with HTTP/2 support.

## Design Decisions

- Use httpx[http2] for multiplexed connections: reduces latency for parallel requests

## Communication with Teammates

- → Researcher: Request HTTP/2 multiplexing research
- ← Researcher: httpx supports HTTP/2 via h2

## Design Decisions (New)

- Agent Teams for Research ↔ Design (bidirectional)

## Skill Pattern Suggestions

### Pattern 1: Research-Design Iteration (Confidence: 0.85)

**Evidence:** Researcher and Architect exchanged findings 5 times, each
exchange refined the design. This back-and-forth is a repeatable pattern.

**Suggested skill:** Already captured as /startproject Phase 2.

### Pattern 2: Parallel File-Isolated Implementation (Confidence: 0.75)

**Evidence:** 3 implementers worked on separate modules with zero conflicts.
Module boundaries were defined by directory ownership.

**Suggested skill:** Already captured as /team-implement.

---

_Generated by checkpointing skill_

Session History Update

Each checkpoint also appends a concise summary to CLAUDE.md:

## Session History

### 2026-02-08

- 12 commits, 15 files changed
- Agent Teams: 1 session (3 teammates, 8/10 tasks completed)
- New skills: /team-implement, /team-review
- Key decisions: Agent Teams for parallel work

This persists across sessions — new sessions load CLAUDE.md and see what happened before.

Skill Pattern Discovery

The checkpoint is automatically analyzed to find reusable patterns:

What it looks for:

• Sequences of commits forming logical workflows
• File change patterns (e.g., test + implementation together)
• Agent Teams coordination patterns (team composition, task sizing)
• Multi-step operations that could be templated

Output: Skill suggestions with confidence scores. High-confidence patterns (>= 0.8) that don't match existing skills are presented to the user for approval.

Execution Flow

/checkpointing
    │
    ├─ 1. Run checkpoint.py (collects git + teams data)
    │     → Generates .claude/checkpoints/YYYY-MM-DD-HHMMSS.md
    │
    ├─ 2. Update CLAUDE.md with session summary
    │
    └─ 3. Spawn subagent for skill pattern analysis
          → Reads checkpoint file
          → Identifies reusable patterns
          → Reports suggestions to user
          → User approves → new skills created in .claude/skills/

When to Run

Timing	Why
セッション終了前	全活動を記録、次セッションへの引き継ぎ
/team-implement 完了後	チーム活動パターンを捕捉
/team-review 完了後	レビューパターンを捕捉
大きな設計決定後	決定のコンテキストを永続化
繰り返しパターンを感じた時	スキル化の発見チャンス

Notes

• チェックポイントは .claude/checkpoints/ に蓄積される（.gitignore 済み）
• ログファイル自体は変更されない（読み取りのみ）
• スキル提案は必ずユーザーがレビューしてから採用すること
• Agent Teams のデータは ~/.claude/teams/ と ~/.claude/tasks/ から収集