Agent.
An LLM-powered system that can take actions, use tools, and pursue multi-step goals autonomously without human input at each step.
An AI agent is a system built around a large language model that can reason about a goal, decide which tools or actions to use, execute those actions, observe the results, and iterate until the task is complete. Unlike a simple chat interaction, an agent operates in a loop — planning, acting, and reflecting across multiple steps.
Agents typically have access to tools such as web search, code execution, file systems, APIs, or databases. The LLM decides when and how to use these tools based on its understanding of the goal and the current state. Popular agent frameworks include LangChain, CrewAI, and AutoGen.
The main challenges with agents are reliability and cost. Because they call the model multiple times per task, errors compound across steps. Agentic systems are an active area of research, with improvements in planning, memory, and error recovery happening rapidly in 2024–2025.