/skill-session-analyzer

name: skill-session-analyzer
description: |
  This skill should be used when the user asks to "analyze session", "evaluate skill execution",
  "check session logs", provides a session ID with a skill path,
  or wants to verify that a skill executed correctly in a past session.
  Post-hoc analysis of Claude Code sessions to validate skill/agent/hook behavior against SKILL.md specifications.
allowed-tools:
  - Read
  - Grep
  - Glob
  - Bash
  - Task
  - Write

Session Analyzer Skill

Post-hoc analysis tool for validating Claude Code session behavior against SKILL.md specifications.

Purpose

Analyze completed sessions to verify: 1. **Expected vs Actual Behavior** - Did the skill follow SKILL.md workflow? 2. **Component Invocations** - Were SubAgents, Hooks, and Tools called correctly? 3. **Artifacts** - Were expected files created/deleted? 4. **Bug Detection** - Any unexpected errors or deviations?

---

Input Requirements

| Parameter | Required | Description | |-----------|----------|-------------| | `sessionId` | YES | UUID of the session to analyze | | `targetSkill` | YES | Path to SKILL.md to validate against | | `additionalRequirements` | NO | Extra validation criteria |

---

Phase 1: Locate Session Files

Step 1.1: Find Session Files

Session files are located in `~/.claude/`:

# Main session log
~/.claude/projects/-{encoded-cwd}/{sessionId}.jsonl

# Debug log (detailed)
~/.claude/debug/{sessionId}.txt

# Agent transcripts (if subagents were used)
~/.claude/projects/-{encoded-cwd}/agent-{agentId}.jsonl

Use script to locate files:

${baseDir}/scripts/find-session-files.sh {sessionId}

Step 1.2: Verify Files Exist

Check all required files exist before proceeding. If debug log is missing, analysis will be limited.

---

Phase 2: Parse Target SKILL.md

Step 2.1: Extract Expected Components

Read the target SKILL.md and identify:

**From YAML Frontmatter:**

• `hooks.PreToolUse` - Expected PreToolUse hooks and matchers
• `hooks.PostToolUse` - Expected PostToolUse hooks
• `hooks.Stop` - Expected Stop hooks
• `hooks.SubagentStop` - Expected SubagentStop hooks
• `allowed-tools` - Tools the skill is allowed to use

**From Markdown Body:**

• SubAgents mentioned (`Task(subagent_type="...")`)
• Skills called (`Skill("...")`)
• Artifacts created (`.hoyeon/drafts/`, `.hoyeon/specs/`, etc.)
• Workflow steps and conditions

Step 2.2: Build Expected Behavior Checklist

Create checklist from SKILL.md analysis:

## Expected Behavior

### SubAgents
- [ ] Explore agent called (parallel, run_in_background)
- [ ] gap-analyzer called before plan generation
- [ ] plan-reviewer called after plan creation

### Hooks
- [ ] PreToolUse[Edit|Write] triggers plan-guard.sh
- [ ] Stop hook validates plan-reviewer approval

### Artifacts
- [ ] Draft file created at .hoyeon/drafts/{name}.md
- [ ] Plan file created at .hoyeon/specs/{name}.md
- [ ] Draft file deleted after OKAY

### Workflow
- [ ] Interview Mode before Plan Generation
- [ ] User explicit request triggers plan generation
- [ ] Reviewer REJECT causes revision loop

---

Phase 3: Analyze Debug Log

The debug log (`~/.claude/debug/{sessionId}.txt`) contains detailed execution traces.

Step 3.1: Extract SubAgent Calls

Search patterns:

SubagentStart with query: {agent-name}
SubagentStop with query: {agent-id}

Use script:

${baseDir}/scripts/extract-subagent-calls.sh {debug-log-path}

Step 3.2: Extract Hook Events

Search patterns:

Getting matching hook commands for {HookEvent} with query: {tool-name}
Matched {N} unique hooks for query "{query}"
Hooks: Processing prompt hook with prompt: {prompt}
Hooks: Prompt hook condition was met/not met
permissionDecision: allow/deny

Use script:

${baseDir}/scripts/extract-hook-events.sh {debug-log-path}

Step 3.3: Extract Tool Calls

Search patterns:

executePreToolHooks called for tool: {tool-name}
File {path} written atomically

Step 3.4: Extract Hook Results

For prompt-based hooks, find the model response:

Hooks: Model response: {
  "ok": true/false,
  "reason": "..."
}

---

Phase 4: Verify Artifacts

Step 4.1: Check File Creation

For each expected artifact: 1. Search debug log for `FileHistory: Tracked file modification for {path}` 2. Search for `File {path} written atomically` 3. Verify current filesystem state

Step 4.2: Check File Deletion

For files that should be deleted: 1. Search for `rm` commands in Bash calls 2. Verify file no longer exists on filesystem

---

Phase 5: Compare Expected vs Actual

Step 5.1: Build Comparison Table

| Component | Expected | Actual | Status |
|-----------|----------|--------|--------|
| Explore agent | 2 parallel calls | 2 calls at 09:39:26 | ✅ |
| gap-analyzer | Called before plan | Called at 09:43:08 | ✅ |
| plan-reviewer | Called after plan | 2 calls (REJECT→OKAY) | ✅ |
| PreToolUse hook | Edit\|Write matcher | Triggered for Write | ✅ |
| Stop hook | Validates approval | Returned ok:true | ✅ |
| Draft file | Created then deleted | Created→Deleted | ✅ |
| Plan file | Created | Exists (10KB) | ✅ |

Step 5.2: Identify Deviations

Flag any mismatches:

• Missing component calls
• Wrong order of operations
• Hook failures
• Missing artifacts
• Unexpected errors

---

Phase 6: Generate Report

Report Template

# Session Analysis Report

## Session Info
- **Session ID**: {sessionId}
- **Target Skill**: {skillPath}
- **Analysis Date**: {date}

---

## 1. Expected Behavior (from SKILL.md)

[Summary of expected workflow]

---

## 2. Skill/SubAgent/Hook Verification

### SubAgents
| SubAgent | Expected | Actual | Time | Result |
|----------|----------|--------|------|--------|
| ... | ... | ... | ... | ✅/❌ |

### Hooks
| Hook | Matcher | Triggered | Result |
|------|---------|-----------|--------|
| ... | ... | ... | ✅/❌ |

---

## 3. Artifacts Verification

| Artifact | Path |