Session Compare Skill for Claude

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

• 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

• 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}

• 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

• 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