Pulse is a built-in tool that periodically collects and sends diagnostic data to Nutanix support for proactive monitoring and troubleshooting. This data includes cluster configuration, performance metrics, and error logs, among other things. Nutanix support can use this data to identify and resolve issues before they become critical, and to provide recommendations for optimizing cluster performance.
NCC (Nutanix Cluster Check) is another tool provided by Nutanix, but it is used for performing manual health checks and diagnostics on the cluster, rather than providing proactive support.
Cluster Heart and Cluster Health are not tools provided by Nutanix, and are not relevant to this question.