What is an AI agent?
A practical explanation of agents, tools, memory, and the loop that turns a model into a system that can act.
A model that can act
An AI agent is a software system that uses a model to decide what to do next. Unlike a chatbot that only returns text, an agent can call tools, inspect results, update its plan, and continue until it reaches a goal.
The useful mental model is a loop: observe, reason, act, and evaluate. The model provides judgment, while your application provides tools, state, limits, and a clear stopping condition.
The building blocks
Reliable agents are assembled from a small set of explicit parts.
- Instructions that define the job and boundaries.
- Tools that expose narrow, typed actions.
- State or memory for facts needed across steps.
- A control loop with time, cost, and iteration limits.
- Observability and policy checks around every external action.
Start smaller than you think
Begin with one workflow and two or three tools. Measure whether the agent chooses the right tool, supplies correct arguments, and stops at the right time before adding autonomy.