/session-compare

name: session-compare
description: >
  Compare two sessions side-by-side using Agent Monitor data — per-model
  token usage (input/output/cache_read/cache_write + compaction baselines),
  pricing engine cost breakdowns, workflow intelligence (complexity scores,
  tool flow transitions, subagent effectiveness), session metadata
  (thinking_blocks, turn_count, turn_duration_ms, usage_extras), and
  full event timelines with all 10+ event types.

Session Compare

Compare two Claude Code sessions side-by-side using Agent Monitor data.

Input

The user provides: **$ARGUMENTS**

This may be:

• Two session IDs: "abc123 def456"
• "best vs worst" — compare highest and lowest productivity sessions
• "latest 2" — compare the two most recent sessions
• A session ID + "vs average" — compare one session against the baseline

Procedure

1. **Identify sessions to compare**:

• If two IDs given: fetch both from `http://localhost:4820/api/sessions/{id}`
• If "best vs worst": fetch sessions, score by completion + cost efficiency, pick extremes
• If "latest 2": `GET /api/sessions?limit=2` (default sort: most recently updated first)
• If "vs average": fetch session + compute averages from last 50 sessions

2. **Gather detailed data** for each session:

• Session metadata: `GET /api/sessions/{id}`
• Events: `GET /api/events?session_id={id}`
• Agents: `GET /api/agents?session_id={id}`
• Cost: `GET /api/pricing/cost/{id}`

3. **Build comparison**:

Overview Comparison

| Metric | Session A | Session B | Difference | |--------|-----------|-----------|-----------| | Status | completed | error | — | | Model | sonnet-4 | sonnet-4 | same | | Duration | 12m 34s | 45m 12s | +32m 38s | | Total Cost | $0.0234 | $0.1456 | +522% | | Events | 45 | 187 | +315% | | Tools Used | 8 | 12 | +4 | | Error Count | 0 | 7 | +7 | | Agents | 2 | 5 | +3 |

Token Comparison

| Token Type | Session A | Session B | Difference | |-----------|-----------|-----------|-----------| | Input | N | N | ±N% | | Output | N | N | ±N% | | Cache Read | N | N | ±N% | | Cache Write | N | N | ±N% | | Efficiency | N% | N% | ±N% |

Tool Usage Comparison

• Tools unique to Session A
• Tools unique to Session B
• Shared tools with usage count comparison
• Error rate per tool in each session

Timeline Comparison

• Side-by-side event timeline
• Where sessions diverged in approach
• Key decision points that led to different outcomes

Agent Activity Comparison

• Agent counts and types
• Subagent strategy differences
• Agent success rates

4. **Analysis**:

• Why one session was more efficient/successful than the other
• Key decisions that made the difference
• Lessons to apply to future sessions

Output Format

Present as a side-by-side comparison report with:

• Executive comparison summary (which session was "better" and why)
• Structured comparison tables with color-coded differences (green = better, red = worse)
• A "Lessons Learned" section with actionable takeaways
• Overall winner declaration with justification