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.
Bitcoin miners use a lot of resources to optimize the earning of bitcoins. For this reason, threat actors try to use other people’s machines to do their mining for them. This detection means that your machine is being used as such.
Malwarebytes can remove Trojan.BitCoinMiner without user interaction. After the scan and removal, a reboot is required. Malwarebytes will prompt you to do this.