AI agents look simple at first.

You take a model, add a prompt, maybe connect a tool, and it works. It feels like you are just making one API call and getting an answer.

That illusion disappears the moment the agent starts doing real work.

In production, an agent is not one call. It is a loop. It may call the model multiple times, retrieve memory, execute tools, retry on failure, and refine its own output.

That is where cost shows up.