Ask about anything that changes - today's news, a stock price, a competitor's pricing page - and Magnus searches the web as part of composing the answer. No setup, no browser window: the search happens inside the model's turn and results come back with source citations.
Magnus decides for himself when an answer depends on current information and searches only then - a question about your own goals never triggers it, a question about this morning's headlines does. He can run several searches in one answer to cross-check.
These are different tools. Web search reads the live web to inform an answer. The web agent (see its own guide) drives an actual browser - clicking, filling forms, logging in - to do things on the web for you. Search is instant and automatic; the agent is deliberate and supervised.