alert http://jabber.org/protocol/amp?action=drop The message is silently discarded but an alert is returned to the sender. XEP-0079: Advanced Message Processing drop http://jabber.org/protocol/amp?action=drop The message is silently discarded. XEP-0079: Advanced Message Processing error http://jabber.org/protocol/amp?action=error The message is not processed and an error is returned to the sender, specifying which rule resulted in failed processing. XEP-0079: Advanced Message Processing notify http://jabber.org/protocol/amp?action=notify The message is processed and a notification message is returned to the sender, specifying which rule was processed. XEP-0079: Advanced Message Processing