A chatbot takes a message and replies. Older chatbots follow scripted menus; modern ones use a language model, often with retrieval over your documents, to write the reply. Either way, the output is text for a person to read. Use one for FAQs, policy questions, website help and first-line support.
An AI agent is given a goal and a set of tools: read an inbox, search a database, create a record, call an API. It decides which tool to use, looks at the result, and continues until the job is done or it needs a person. Use one for multi-step back-office work where the steps vary from case to case.
The chatbot vs AI agent question is really about risk. A chatbot that is wrong gives a bad answer. An agent that is wrong can send an email, change a record or move money. So agents need narrower permissions, logs and human approval at the points that matter. We build both through AI agent development and RAG chatbots.