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 hamsurang/kit --skill vitestgit clone --depth 1 https://github.com/hamsurang/kitWrote 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/hamsurang/kit/vitest)<a href="https://agentmods.dev/skills/hamsurang/kit/vitest"><img src="https://agentmods.dev/badge/skills/hamsurang/kit/vitest/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/hamsurang/kit/vitest"><img src="https://agentmods.dev/badge/skills/hamsurang/kit/vitest.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00093 | $0.00712 |
| Opus 5.5 | $0.00037 | $0.00285 |
| Sonnet 5.5 | $0.00019 | $0.00142 |
| Haiku 4.5 | $0.00009 | $0.00071 |
Grade A, and why
vitest 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 1mo 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 — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Vitest Skill
Contents
Quick Start
Minimum setup:
npm install -D vitest
// vitest.config.ts
import { defineConfig } from 'vitest/config'
export default defineConfig({
test: {
environment: 'node',
},
})
First test (src/math.test.ts):
import { describe, it, expect } from 'vitest'
import { add } from './math'
describe('add', () => {
it('returns the sum of two numbers', () => {
expect(add(1, 2)).toBe(3)
})
})
npx vitest # watch mode
npx vitest run # single run (CI)
When This Skill Activates
- User asks to write a test for a function, component, or module
- User asks how to configure Vitest or integrate it into an existing Vite project
- User's tests are failing and they need help diagnosing the error
- User asks about mocking, spying, or stubbing in Vitest
- User wants to measure or enforce test coverage
Behavior Guidelines
- Prefer Vitest-native imports — import
describe,it,expect,vi, etc. from'vitest', not from@jest/*packages. - Respect the existing config — read
vitest.config.tsorvite.config.tsbefore suggesting configuration changes. - Match the project's test style — check existing test files for naming conventions (
*.test.tsvs*.spec.ts,itvstest) and follow them. - Use
vifor all mocking — never suggestjest.fn(),jest.mock(), etc. - Run tests to verify — after writing or modifying tests, suggest running
npx vitest runto confirm they pass.
References Loading Guide
Load additional context files based on what the user needs:
| Situation | Load |
|---|---|
Questions about vitest.config.ts, environments, globals, setupFiles |
references/config.md |
Questions about describe, it, test, expect, hooks |
references/api.md |
Questions about vi.fn(), vi.mock(), vi.spyOn(), timers, globals |
references/mocking.md |
Questions about coverage providers, thresholds, --coverage flag |
references/coverage.md |
What ships with it
4 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.
- 1mo ago First seen · 85 lines · 93 tokens per session scan A d41744ccad84
vitest is a skill published in the GitHub repository hamsurang/kit (19 stars, last pushed 5mo ago), licensed MIT. It adds 93 tokens to every session and 712 once invoked, about $0.0004 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 2026-08-30.
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