AI agents are intelligent digital assistants that can understand, process information, and take action to complete tasks. The source explains that AI agents are like the practical, hands-on counterpart to AI, which is like raw brainpower. They compare AI agents to babysitters who are given instructions and then use those instructions to take care of tasks. AI agents are trained by developers using data and can be customized to fit individual needs. They can interact with users through interfaces like chat windows or voice assistants. The source emphasizes the potential impact of AI agents on work and daily life, explaining how they can automate tasks, improve efficiency, and ultimately revolutionize the way we work and live.