Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add hoangsonww/Claude-Code-Agent-Monitor --skill session-comparegit clone --depth 1 https://github.com/hoangsonww/Claude-Code-Agent-MonitorWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/hoangsonww/claude-code-agent-monitor/session-compare)<a href="https://agentmods.dev/skills/hoangsonww/claude-code-agent-monitor/session-compare"><img src="https://agentmods.dev/badge/skills/hoangsonww/claude-code-agent-monitor/session-compare/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/hoangsonww/claude-code-agent-monitor/session-compare"><img src="https://agentmods.dev/badge/skills/hoangsonww/claude-code-agent-monitor/session-compare.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00082 | $0.00818 |
| Opus 5 | $0.00041 | $0.00409 |
| Sonnet 5 | $0.00016 | $0.00164 |
| Haiku 4.5 | $0.00008 | $0.00082 |
Grade A, and why
session-compare scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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
- If two IDs given: fetch both from
-
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}
- Session metadata:
-
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
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 8d ago First seen · 91 lines · 82 tokens per session scan A 1c38d4673983
session-compare is a skill published in the GitHub repository hoangsonww/Claude-Code-Agent-Monitor (989 stars, last pushed 3d ago), licensed MIT. It adds 82 tokens to every session and 818 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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