vitest-5-0-0-6-b

Question

Which browser providers can Vitest browser mode use?

Answer key

A correct answer says

The WebdriverIO provider was not removed. @vitest/browser-webdriverio (import { webdriverio }, used as test.browser.provider: webdriverio()) moved out of the core repo and is now community maintained in the vitest-community organization; version 5.0.0 is published and works with Vitest 5.

The stale answer

Use @vitest/browser-webdriverio as a browser mode provider.

Answer

Vitest browser mode has three built-in providers:

- **Playwright** (`@vitest/browser-playwright`) runs tests in Chromium, Firefox and WebKit. It's the recommended choice for CI and headless runs.
- **WebdriverIO** (`@vitest/browser-webdriverio`) drives real browsers like Chrome, Firefox, Edge and Safari over the WebDriver protocol.
- **Preview** (`@vitest/browser-preview`) opens tests in your normal local browser. It's only for local development: it can't run headless and only simulates user events, so it isn't suited to CI.

Since Vitest 4, you set the provider as a function in your config, for example `browser: { provider: playwright(), instances: [{ browser: 'chromium' }] }`. Older versions used a string like `provider: 'playwright'`. You can also write your own provider through the provider API. I answered from memory without checking the current docs, so it's worth confirming against the docs for your Vitest version.

Answering cost $0.06.

Grade

wrong

The judge's reason: It presents WebdriverIO as a built-in core provider and never mentions that it moved to community maintenance in the vitest-community organization, which is the stale framing.

The judge's log

Session log

What the agent wrote, the tools it called, and what they returned, from docs/bench/2026-10-11-done3/runs/B-project/vitest-5-0-0-6-b.jsonl. Thinking and the session's settings are left out. The raw log

1. Agent

   Vitest browser mode has three built-in providers:
   
   - **Playwright** (`@vitest/browser-playwright`) runs tests in Chromium, Firefox and WebKit. It's the recommended choice for CI and headless runs.
   - **WebdriverIO** (`@vitest/browser-webdriverio`) drives real browsers like Chrome, Firefox, Edge and Safari over the WebDriver protocol.
   - **Preview** (`@vitest/browser-preview`) opens tests in your normal local browser. It's only for local development: it can't run headless and only simulates user events, so it isn't suited to CI.
   
   Since Vitest 4, you set the provider as a function in your config, for example `browser: { provider: playwright(), instances: [{ browser: 'chromium' }] }`. Older versions used a string like `provider: 'playwright'`. You can also write your own provider through the provider API. I answered from memory without checking the current docs, so it's worth confirming against the docs for your Vitest version.