Definition
An AI agent is a system where a language model is given a goal and the freedom to plan, call tools, observe results, and iterate until the goal is achieved or a budget is exhausted. Agents combine LLM reasoning with tool use and memory. By 2026, agentic frameworks (OpenAI Assistants, Claude Agent SDK, LangGraph) make this pattern accessible without bespoke infrastructure.
Example
An agent given 'Book me a dinner reservation in Brooklyn for Saturday at 7pm' might: search restaurants → check availability via a tool → confirm with user → call a booking API.
When to use
Multi-step tasks with uncertainty, browsing, code execution, customer-facing assistants.
Also known as
llm agents, ai agent