Try it on an example
The repository has a small site with five responsive bugs left in on purpose, and no dependencies, so you can see what breakhound does before running it on your own app.
bash
git clone https://github.com/Seybel/breakhound.git
cd breakhound/examples/acme
npx @seybel/breakhoundbreakhound starts the site with its dev script, follows its links to all three pages, and finds:
| Page | Bug | Widths |
|---|---|---|
/ | The heading keeps its 64px desktop size, so a word of it is wider than a small phone | 320 to 470px |
/ /pricing /about | Six fixed-width nav links wrap onto two lines before the menu button takes over | 768 to 907px |
/pricing | The comparison table is 640px wide at every width | 320 to 659px |
/about | The photo is a fixed 280px in a column narrower than that, and covers the text | 640 to 879px |
Then try the fixing loop: npx @seybel/breakhound mcp install and ask your coding agent to fix the breakhound issues, or npx @seybel/breakhound prompt --copy and paste it in.
To try the Chrome extension on it, run npm run dev, open http://localhost:4173 and right-click the page: Scan with breakhound.