An LLM and an agent are related, but they are not the same thing.
The model is the reasoning or generation engine. The agent is the surrounding system that gives the model a goal, tools, memory, state, and a control loop for taking actions.
A helpful distinction
If you type a question into a model and get back a response, that does not automatically mean you are using an agent. You may just be using a language model in a straightforward request-response pattern.
Once software starts wrapping that model with tool calls, retries, planning, or multi-step execution, you are moving into agentic territory.
That distinction matters because many claims about “AI agents” are really claims about the system around the model, not the model alone.