# Session Debug

Debug a specific session by inspecting its full event chain (PreToolUse, PostToolUse...

- Repository: https://github.com/hoangsonww/Claude-Code-Agent-Monitor (1136 stars)
- Category: Testing
- License: MIT
- Last updated: 2026-10-31
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add hoangsonww/Claude-Code-Agent-Monitor --skill session-debug -g -a claude-code -y`
Codex: `npx skills add hoangsonww/Claude-Code-Agent-Monitor --skill session-debug -g -a codex -y`
Cursor: `npx skills add hoangsonww/Claude-Code-Agent-Monitor --skill session-debug -g -a cursor -y`
Gemini CLI: `npx skills add hoangsonww/Claude-Code-Agent-Monitor --skill session-debug -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add hoangsonww/Claude-Code-Agent-Monitor`

## Description

Debug a specific session by inspecting its full event chain (PreToolUse, PostToolUse, Stop, SubagentStop, Compaction, APIError, TurnDuration, Notification events), agent hierarchy (recursive parent/child tree with subagent_type and depth), token usage with compaction baselines, workflow intelligence data (orchestration DAG, error propagation by depth), and session metadata (thinking_blocks, turn_count, total_turn_duration_ms).

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Session Debug

Debug and inspect a Claude Code session from Agent Monitor data.

## Input

The user provides: **$ARGUMENTS**

This may be:
- A session ID to debug
- "latest" or "last" for the most recent session
- "errors" to find and debug the most recent errored session

## Procedure

1. **Identify the target session**:
   - If session ID given: `GET /api/sessions/{id}` from `http://localhost:4820`
   - If "latest": `GET /api/sessions?limit=1` (default sort: most recently updated first)
   - If "errors": `GET /api/sessions?limit=10&status=error`

2. **Collect full session data**:
   - Session metadata: status, model, cwd, timestamps, duration
   - Events: `GET /api/events?session_id={session_id}`, full event timeline
   - Agents: `GET /api/agents?session_id={session_id}`, all agents in session
   - Cost: `GET /api/pricing/cost/{session_id}`

3. **Analyze the session**:

   ### Session Lifecycle
   - Start time → first event → last event → end time
   - Status transitions (active → working → completed/error)
   - Total duration and active-vs-idle time

   ### Event Chain Analysis
   - Chronological event list with timestamps and durations
   - Identify the **critical path** (longest chain of dependent events)
   - Flag events that took unusually long
   - Highlight error events with full error context

   ### Agent Inspection
   - List all agents: type, task, status, duration
   - Subagent tree visualization (parent → children)
   - Agents that failed and their last known state
   - Agent switching patterns (when and why new agents spawned)

   ### Tool Execution Trace
   - Every tool invocation in order with: tool name, duration, success/failure
   - Failed tool calls with error messages
   - Tool retry patterns (same tool called multiple times)

   ### Anomaly Detection
   - Events out of expected order
   - Gaps in event timeline (>30s with no events)
   - Duplicate events or agent states
   - Token usage spikes (compaction indicators)

The rest: https://github.com/hoangsonww/Claude-Code-Agent-Monitor/blob/HEAD/plugins/ccam-devtools/skills/session-debug/SKILL.md