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