AI Glossary
AI agent
Also known as: Autonomous agent · LLM agent
An AI agent is a system where an LLM decides, in a loop, which tools to use (fetch data, call APIs, run code) to reach a goal, until it finishes or asks for help.
Chat vs. agent
In chat, the model only answers. An agent acts: it picks a tool, observes the result and decides the next step.
Building blocks
- Model: the LLM that makes decisions.
- Tools: functions with well-defined inputs and outputs.
- Memory: the context the agent carries between steps.
- Guardrails: max steps, budget, actions that require human approval.
The risk
The more power the tools have, the bigger the damage from a mistake or a prompt injection. Production agents need least-privilege permissions, audit logs and a clear way to stop.
Go deeper in the book
AI Agents in Practice
Build agents that get work done and know when to stop.