vitest: a Claude Code skill by Anthony Fu
For JavaScript and TypeScript developers writing or fixing Vitest tests and config. Skip it if your project runs Jest, Mocha or another runner and you are not moving to Vitest.
- Score
- 71of 100
- Rank
- #163of 239
- Installs
- 47.6Kon skills.sh
- Security
- Clear 5 scanners
- Updated
- 2026
- Context
- ~45tokens always
Install
npx skills add https://github.com/antfu/skills --skill vitest Run it in your terminal. View the source
Using the Claude app rather than Claude Code? You can add a skill there too. How to add it in the app
What does vitest do?
vitest is a skill that gives Claude a reference map of the Vitest test runner, written against Vitest 5.1.0-beta.1. The main file is an index: it sorts topics into core, feature and advanced tables and points each one to its own reference page. Core pages cover defineConfig, the CLI, test and describe, expect matchers and hooks such as aroundEach. Feature pages cover vi mocks, snapshots, V8 or Istanbul coverage, fixtures through test.extend, sharding, tags, reporters and Tinybench benchmarks. Advanced pages cover fake timers, jsdom and happy-dom environments, expectTypeOf type tests and multi-project workspaces. It holds no workflow of its own; Claude reads the page that fits the task.
When should you use vitest?
Use it when
- You are adding unit tests to a Vite project
- You need to mock a module, timer or date in Vitest
- You want coverage or sharding set up in vitest.config
Skip it when
- Your tests run on Jest and will stay there
- You want a step-by-step testing workflow, not reference notes
What it needs and what it can touch
You need
- Node.js and Vitest in your project
From reading its instructions, not from running it.
Why it scores 71
Strongest on upkeep (100 of 100), weakest on adoption (52).
Is vitest safe to install?
Every scanner that checked it passed it. Scanners often miss what other scanners catch, and a skill can change after a scan. Read its source before you install it.
| Scanner | Result | Date |
|---|---|---|
| Gen Agent Trust Hub | Passed | Oct 23, 2026 |
| Socket | Passed | Oct 23, 2026 |
| Snyk | Low risk | Oct 23, 2026 |
| Runlayer | Low risk | Feb 26, 2026 |
| ZeroLeaks | Passed | Apr 15, 2026 |
Details
- Installs
- 47,597
- Repository stars
- 6,064
- Last repository change
- Tokens always loaded
- about 45
- Tokens when used
- about 833
- License
- MIT
- Data confidence
- High
Did it do the job for you?
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vitest