In artificial intelligence (AI), an agent refers to an entity that perceives its environment through sensors and acts upon that environment using actuators, often with the goal of achieving specific objectives. Agents can range from simple programs designed for tasks like web searching or data analysis to more complex systems, such as autonomous robots or intelligent virtual assistants, that adapt and learn from their interactions. They can operate based on predefined rules or learn from experience, employing techniques like machine learning and reinforcement learning to improve their performance over time. AI agents are central to many applications, from decision-making in dynamic environments to human-computer interaction.