What is the difference between an AI function and an assistant?

An assistant is the artificial intelligence agent that directly chats or communicates with the user via email or web widget. An AI function, on the other hand, is a tool in the hands of this assistant. For example, while an assistant on its own can only provide general information, when assigned a "query_stock" function, it can trigger this function to query the database when a customer asks about stock and return exact stock numbers to the client.