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name: checkpoint-session description: Manage session lifecycle, learning extraction, and context metrics. Use when starting/ending sessions, analyzing workflows for learnings, querying knowledge graph, or checking session metrics. allowed-tools: Bash, Read

Checkpoint Session Skill

Manage Claude session lifecycle, learning extraction, and context metrics.

When to Use

• Starting a new Claude session (auto-run via SessionStart hook)
• Ending a session and extracting learnings
• Analyzing completed workflows for patterns and mistakes
• Querying the knowledge graph for relevant learnings
• Checking session metrics and usage patterns

CLI Reference

All commands use the checkpoint CLI:

Copybun run checkpoint <command> [args...]

Session Lifecycle Commands

Session Start

Initialize session context and check for resumable workflows:

Copybun run checkpoint session-start [--branch <name>] [--issue <number>]

What it does:

• Detects current git branch and modified files
• Cleans up stale workflows (>24 hours)
• Prompts for workflow resume if active workflows found
• Outputs session context summary

Session End

Record session metrics and extract learnings:

Copybun run checkpoint session-end [options]

Options:

• --workflow-id <id> - Associate with specific workflow
• --session-id <id> - Session identifier (auto-detected from session-start)
• --learnings-injected <n> - Count of learnings used in session
• --start-time <iso> - Session start timestamp
• --compacted - Flag if context was compacted
• --interrupted - Flag if session was interrupted
• --review-findings <n> - Count of review findings
• --files-read <n> - Count of files read

Learning Commands

Analyze Workflow

Extract learnings from a completed workflow:

Copybun run checkpoint learning analyze <workflow-id> <dev-plan-path>

Analyzes:

• Planned vs actual commits
• Deviations from plan
• Review findings and fixes
• Patterns to repeat
• Mistakes to avoid

Query Learnings

Find relevant learnings from the knowledge graph:

Copybun run checkpoint learning query [options]

At least one filter required:

• --code-area <area> - Filter by code area (e.g., "authentication", "database")
• --file <path> - Filter by file path
• --issue <number> - Filter by source issue number

Returns:

• Learning content
• Confidence scores
• Related patterns
• Related mistakes

Metrics Commands

List Session Metrics

View recorded session metrics:

Copybun run checkpoint metrics list [issue-number]

Shows per session:

• Files read
• Compaction status
• Duration
• Review findings
• Learnings injected/captured

Metrics Summary

View aggregate metrics:

Copybun run checkpoint metrics summary

Shows:

• Total sessions
• Compaction rate
• Average files read
• Average learnings injected/captured
• Total review findings

Example: Full Session Flow

Copy# 1. Session starts (auto-run by hook)
bun run checkpoint session-start --branch feat/issue-394

# 2. During session: use /work-on-issue or /auto-issue
#    These use the workflow checkpoint commands

# 3. After workflow complete: analyze for learnings
bun run checkpoint learning analyze "workflow-394-xxx" ".claude/dev-plans/issue-394.md"

# 4. Session ends (capture metrics)
bun run checkpoint session-end --files-read 42 --review-findings 3

Example: Query Knowledge Before Starting Work

Copy# Find learnings about similar code areas
bun run checkpoint learning query --code-area "badge-verification"

# Find learnings from a related issue
bun run checkpoint learning query --issue 380

# Find learnings about a specific file
bun run checkpoint learning query --file "packages/openbadges-types/src/ob3.ts"

Integration with Hooks

The session commands integrate with Claude Code hooks:

Session metadata is automatically passed between hooks via temp files.