Hello,

In our May newsletter, we shared how Wallaby's CLI and AI tools give coding agents access to live test results and runtime data. Since then, we've been working on helping agents use that feedback to write better tests.

We're excited to introduce Wallaby for Coding Agents, including a new set of skills for writing tests and improving existing ones. They help your agent check that its tests catch real bugs, giving you more confidence in the code you ship.

Get started

Run this in your project's terminal and choose your coding agent:

npx skills add wallabyjs/skills

Use /wallaby write in your prompts or automated workflows. Your agent writes or updates tests for a feature or bug fix, covers the expected behavior and edge cases, and verifies its assertions.

Use /wallaby improve to strengthen the tests you already have. Your agent finds weak assertions and missing cases, and removes duplicate checks. You can focus on a file, a directory, or the changes in your branch.

More examples and setup options.

AI tests that catch real bugs

AI can write low-value tests that pass without checking much. Wallaby helps your agent strengthen assertions and verify that tests catch regressions.

In our internal Wallaby Bench evaluations, agents using Wallaby and its skills scored up to 40% better than agents using Vitest or Jest alone. The combined score measures code and test quality, speed, and token efficiency.

How it works

Wallaby lets your agent see what each test actually does. It can find untested branches, follow execution across files, and inspect runtime values without adding logs.

Wallaby's skills guide your agent to use this feedback efficiently, requesting the details it needs for each check. They help it verify assertions against intended behavior and strengthen weak tests, using mutation testing when needed.

Read more in the blog post.

Your Wallaby access

Your active Wallaby license already includes local access. You can use Wallaby for Coding Agents on the same machine as your editor extension, without any extra activation.

If you don't have a license, yours has expired, or you want to run Wallaby in a container or the cloud, you can try it for free during beta.

Thanks for reading!

Regards, The Wallaby Team