Definition: irregularity encountered by an agentsoftware that collects data published from one or more piece(s) of equipment, organizes that data in a structured manner, and responds to requests for data from client software systems by providing a structured response in the form of a response document that is constructed using the semantic data model of a Standard. in a response documentelectronic document published by an MTConnect Agent in response to a probe request, current request, sample request or asset request. that may or may not conform to the MTConnect Standard.