The Standard Agent assists the Management Server in the discovery of storage resources.
See About the Management Server.
You can install Standard Agents to enable discovery, monitoring, and reporting of the storage resources that are connected to the hosts in your network.
Like the Management Server, the Standard Agent includes the explorers that discover information about the hardware (HBAs) and software in your storage network.
Before CommandCentral 5.2, the Standard Agent was known as the managed host.