Cerebellum is a browser automation system that treats web browsing as graph traversal where webpages are nodes and user actions are edges. It uses an LLM to analyze page content and interactive elements, decide the next action based on current state, execute browser operations through Selenium, and iteratively work toward a user-defined goal. Currently it supports Claude 3.5 Sonnet as the ActionPlanner and can fill forms, handle tabs, and accept runtime instructions to adjust browsing strategies.