vitest

vitest is an open-source testing skill for Claude Code and compatible agents, published by antfu. Its author describes it as: “Vitest fast unit testing framework powered by Vite with Jest-compatible API. Use when writing tests, mocking, configuring coverage, or working with test filtering and fixtures.”. The project has 5.8k stars on GitHub and is available under the MIT license. Add it to your setup with `git clone https://github.com/antfu/skills ~/.claude/skills/vitest`.

What vitest does

Vitest is a next-generation testing framework powered by Vite. It provides a Jest-compatible API with native ESM, TypeScript, and JSX support out of the box. Vitest shares the same config, transformers, resolvers, and plugins with your Vite app.

Installation

Add vitest to your agent with:

git clone https://github.com/antfu/skills ~/.claude/skills/vitest

Always review a skill's source before installing it. This command comes from the skill's public repository; the linked repo is the source of truth for exact setup steps.

What's inside

The SKILL.md for vitest is organised into these sections:

• Core
• Features
• Advanced

When to use it

Reach for vitest when you want testing help from your agent without writing the same instructions every session. Load the skill and the agent picks it up automatically for relevant tasks.

Strengths

• Clear MIT license — safe to read and adapt
• Ships in antfu/skills, an established project with 5,770 GitHub stars
• Actively maintained (recent commits)

Topics

Frequently asked questions

What does vitest do?

Vitest fast unit testing framework powered by Vite with Jest-compatible API. Use when writing tests, mocking, configuring coverage, or working with test filtering and fixtures.

How do I install vitest?

Run git clone https://github.com/antfu/skills ~/.claude/skills/vitest in your agent, then reload your skills. Review the source at https://github.com/antfu/skills before installing.

Is vitest free to use?

Yes. vitest is free and open source under the MIT license, so you can read, run, and adapt it within that license's terms.

Where does vitest come from?

vitest ships inside antfu/skills, a repository that contains 19 catalogued skills in total. The repository's 5,770 GitHub stars apply to that whole collection, not to this skill on its own.