Extension Real Browser Testing

Use this skill when you need to validate extension behavior in a real browser instead of guessing from unit tests, jsdom, or static screenshots.

When to use

Apply this skill when:

• the task requires validating an extension in a real browser, not just unit tests
• the bug only reproduces after build, zip, or unpacked installation
• the issue is browser-specific or version-specific
• you need to inspect live content script DOM, shadow DOM, popup state, or service-worker targets
• you need stronger evidence than component tests or jsdom can provide
• a UI PR needs screenshots rendered from the real extension behavior

Quick reference