Heloo,
Using NPM , is it possible to create an alert based on packet drop rate in a specific CoS ?
Perhaps poll this MIB: cbQosCMDropBitRate by its OID. Then create an alert for this poller. SNMPwalk or vendor documentation could be helpful.
"This document describes how to extract the various values related to Class Based Quality of Service (QoS) details (CISCO-CLASS-BASED-QOS-MIB) applied against Control Plane with Simple Network Management Protocol (SNMP)."
https://www.cisco.com/c/en/us/support/docs/ip/simple-network-management-protocol-snmp/119031-technote-router-00.html