Hi @ali99 ,
to trace information back to the OCS server, an agent is needed, mainly because of formatting data in XML format and that it supports the communication security with the server (certificate).
Without an agent, you also have the option to retrieve device informations via the SNMP protocol (for computers, printers, Ethernet switches, routers, NAS, etc.) but these informations are more complex to recover and you need an OCS agent to trigger the SNMP.
Note: With OCS, SNMP features are more mature on Linux than Windows.