If the leader receives a short message about his subordinates, what will the general leader do?

You mean A sends a message to the leader and tells B about it. There are many such phenomena, and I usually deal with them like this:

First, consider the sender's intention. If it belongs to the category of reporting violations, it shall keep confidential the informants and take appropriate forms to investigate. If it belongs to the category of character evaluation, I will judge for myself and be vigilant to the sender. If it is a reminder, I will pay attention.

Second, on the surface, you should be sure of the sender. After all, it also shows that people trust you and are willing to tell you something. If no one tells you the truth (true or false), the leader will become deaf.