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 mgiovani/cc-arsenal --skill vrt-checkgit clone --depth 1 https://github.com/mgiovani/cc-arsenalWrote 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/mgiovani/cc-arsenal/vrt-check)<a href="https://agentmods.dev/skills/mgiovani/cc-arsenal/vrt-check"><img src="https://agentmods.dev/badge/skills/mgiovani/cc-arsenal/vrt-check/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/mgiovani/cc-arsenal/vrt-check"><img src="https://agentmods.dev/badge/skills/mgiovani/cc-arsenal/vrt-check.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 | $0.00180 | $0.01943 |
| Opus 5.5 | $0.00072 | $0.00777 |
| Sonnet 5.5 | $0.00036 | $0.00389 |
| Haiku 4.5 | $0.00018 | $0.00194 |
Grade A, and why
vrt-check 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 22d 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 — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.
VRT Check
Run visual regression tests, then triage every failure by eye before touching a snapshot. The workflow's only real risk is rubber-stamping --update on a diff nobody looked at: everything below exists to prevent that.
Step 1: Discover the tooling
Never assume a command. Different repos wire VRT through different tools. Look for, in order:
| Order | Tool | Look for |
|---|---|---|
| 1 | Task runner targets | just --list or `grep -E 'visual |
| 2 | package.json scripts | grep -A2 '"scripts"' package.json for chromatic, test:visual, storybook:test, playwright test.*visual |
| 3 | Storybook test-runner | Presence of .storybook/test-runner.ts or @storybook/test-runner in package.json |
| 4 | Playwright screenshot tests | toHaveScreenshot( calls in *.spec.ts, or a playwright.config.* with snapshotDir/toMatchSnapshot settings |
| 5 | Chromatic | chromatic.config.json or a chromatic devDependency; these run in CI and produce a web UI, not local diff images. Say so and point the user there instead of trying to fake a local diff. |
| 6 | Loki | .loki config or loki devDependency |
Base each check on the actual output of the command you ran (ls, grep, just --list), never assert a file is absent without having listed the directory. If two of these are present, ask the user which one is authoritative rather than running both. If none are found, stop and say so, do not invent a screenshot workflow.
For an unfamiliar repo, where a subagent/Task tool is available, delegate this discovery to it rather than grepping inline yourself; otherwise run the greps above directly. Either way, keep the discovered commands around for the rest of the run.
Step 2: Run the diff
Run the discovered diff target, not the update target, even if the user asked to "fix the visual tests": you need to see what changed before deciding anything should be updated.
What ships with it
2 files 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.
- 22d ago Changed · -1 lines cdb9a6c56094
- 1mo ago Changed · +1 lines 1644fc912674
- 1mo ago Changed · +2 lines effa56dcab98
- 1mo ago First seen · 101 lines · 180 tokens per session scan A 1b2d0d2dff07
vrt-check is a skill published in the GitHub repository mgiovani/cc-arsenal (8 stars, last pushed 2d ago), licensed MIT. It adds 180 tokens to every session and 1,943 once invoked, about $0.0007 per session on Opus 5.5. 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 2026-08-31.
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