— Skill

Addy Browser Testing with DevTools

Agents invent why the button “should work” — this skill plugs Chrome DevTools MCP so the agent inspects DOM, console, network, and performance in a real browser.

What changes

Uses Chrome DevTools MCP for live browser diagnosis: DOM inspection, console errors, network analysis, performance profiling, and visual verification with runtime data.

When

Use Addy Osmani’s browser-testing-with-devtools skill when you need live browser diagnosis via Chrome DevTools MCP — DOM, console, network, performance, or visual checks with real runtime data.

Boundary vs claude-webapp-testing: this card is DevTools manual/agent diagnosis against a running page (inspect, profile, verify). claude-webapp-testing is Playwright / webapp testing that leaves durable scripts you can commit. Use DevTools when the question is “what is the browser doing right now?”; use Playwright when the outcome should be an automated test file.

Good fits:

• Console errors only visible after a real click path.
• Network waterfalls / failed requests in staging.
• Layout or a11y checks that need the live accessibility tree.
• Perf profiling before you micro-optimize blind.

Skip it when you need committed Playwright coverage (claude-webapp-testing), ad-hoc computer-use click QA (claude-computer-use-qa), or code-only review without a browser (addy-code-review-and-quality).

How to start

Install with `npx skills add addyosmani/agent-skills --skill browser-testing-with-devtools`. Configure Chrome DevTools MCP, open the app URL, and ask for a DevTools-backed diagnosis.

Use the browser-testing-with-devtools skill (Chrome DevTools MCP — NOT Playwright script generation).
URL: [http://localhost:PORT or staging]. Flow to exercise: [steps].
Inspect with DevTools: DOM state, console errors, failed network calls, and obvious a11y issues.
For each finding: evidence from DevTools + likely cause + fix. No guessed root causes without runtime data.
If you meant durable Playwright tests instead, say so and stop — that is claude-webapp-testing.