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 a generic detection for Trojans that are capable of disabling antivirus (AV) programs.
Malwarebytes can remove this Trojan without further user interaction once it is installed and running. Depending on the AV software being disabled and the method of doing so, users may have to re-install the affected software.