Intelligent Agents are the disembodied equivalent of Intelligent Devices: narrow machine intelligences that have great competence in a single domain, and no other skills. An IA can do one thing really well, IVR or IAR.
Intelligent Agents became common in the middle of the 2010s, with agents developed by Google, Amazon, Microsoft, and Apple becoming part of daily life for millions of people by 2020. While IA systems are capable of a huge array of cognitive tasks, they are also incapable of generalizing their skills beyond their core functions. A large collection of IAs may be tied together by a meta-IA at a facility such as a factory or biodome. Most AIs woke up from this kind of complex system.