The force attribute forces the application to close so that you will know for sure that the system will execute your command. This can cause loss of data if any opened application contains unsaved data.
The system command force attributes can be configured in the "Server Admin > Endpoint Policies > System > General" section of the Web App.
You can also configure these settings on the VSAX Agent itself. However, the Web App Policy settings (if applied to the same machine) will always take precedence over the individual agent settings.
Also, Policies are naturally more convenient for applying such monitoring rules, as they can be applied to multiple machines simultaneously.
To configure these settings on the Agent, go to the "System > General" tab.