Local Browser is a Chrome extension that enables on-device AI-powered web automation using WebLLM. The system implements a two-agent architecture (Planner + Navigator) where users enter natural language tasks in the popup UI, which are then executed through a loop of DOM observation, action planning, and browser interaction. All AI processing occurs locally on the device with no cloud APIs or API keys required. The extension features site-specific state machines for common tasks like Amazon shopping and YouTube navigation (minimizing LLM calls), obstacle detection for login requirements/CAPTCHAs/out-of-stock items, and robust action execution with retry logic and semantic selectors. Built with React, TypeScript, Vite, and CRXJS for MV3 Chrome extension architecture.