Trojan.Agent refers to a generic Trojan malware detection. It is used for detections that are either associated with no specific malware families or not enough information is available to pinpoint the malware family.
This is the generic detection for Trojans that are used in click fraud, which is a form of ad fraud. These continuously make connections to websites, consequently awarding threat actors with revenue on a pay-per-click manner.
Malwarebytes can remove Trojan.Clicker without further user interaction.