Pending Actions

Pending Actions Cause
Requires Patching This indicates a server side MOM patch has been applied and there is a client component that can be pushed to the client that is pending. 
Approve Manual Agent Install This is the most common item and it is normal to see this.  This indicates a new client has contact MOM that was installed from WSUS/SCCM or even manually via command line.  There is a MOM script that runs every hour :45 min after the hour that approves these clients creating an individual discovery rule for the client as well as moving the client into agent-managed computers
Install Agent This is typically the norm in a non-FCS MOM environment. This typically appears because there is a Discovery Rule created for a system that does not currently exist in MOM.
Uninstall Agent In an FCS MOM environment this typically means one of two things.  Either the Discovery rule for that client is missing or the client does not exist in Active Directory any more.  MOM discovery runs nightly and if the system has been pruned out of AD the client will be put into Pending Uninstall.

Discovery Rules

In FCS there should always be 1 discovery rule per system. 

FCS does not use any wildcard rules or exclude rules.  Rules for client machines follow the format as follows:

Rule Type Include
Match Pattern equals
Domain NETBIOS NAME OF CLIENTS, FQDN of the domain for the Management Server object
Computer Type Servers and Clients
Initial Management Mode Agent-Managed
Include Domain Controllers Yes
Verify No for clients, Yes for the Management Server,  Verify means that it will actually try to contact the client, FCS does not try to do this by default.