A slow site loses visitors, and a low mobile score does not tell you which fix comes first. Heavy images, fonts and tracking scripts are the usual causes. These add-ons let the assistant measure the page in a real browser, so it fixes the real cause and checks the result.
Free picks (tested by us)
Most useful first. Each one was installed on a clean test system; start with the first, try it, then add the next.
Lets your assistant open your site in Chrome, read its errors and check its speed.
Test: installs cleanly; its main features need an account we did not use. Not yet used on real work.
Good forWeb developers, Build an appWatch outIt controls Chrome and can read page content, cookies in the browser it controls, and network traffic. Use a fresh browser profile.
For Claude CodeAlso works with Codex CLI and Gemini CLI — see all steps