Build an AI-Powered QA Agent with Agent Browser, Vercel AI SDK, and LLM Gateway

What if you could test your web app by just describing what to test in plain English? No Selenium scripts, no Cypress configs — just tell an AI agent "test the signup flow" and watch it navigate, click, type, and verify results in a real browser. That's exactly what we're building in this article: a QA testing agent that combines Agent Browser for headless browser control, the Vercel AI SDK for tool-calling orchestration, and LLM Gateway as the unified LLM provider. The full source code is available at github.com/theopenco/llmgateway-templates/templates/qa-agent . How It Works The architecture is straightforward: User describes a test in natural language (e.g., "Navigate to the login page, enter invalid credentials, and verify an error is shown") Vercel AI SDK sends the prompt to an LLM via LLM Gateway with browser tools attached The LLM decides which browser actions to take — navigate, snapshot, click, type, etc. Agent Browser executes those actions on a real headless Chromium instanc