short answer: not really
long answer: pvecm and pvesm sometimes operate on the whole cluster or rather files in /etc/pve which are used by the whole cluster, depending on the actual command. pct and qm are always related to the current node, but some commands have a target node parameter as well.
most of the information is in /etc/pve, so for read-only access you can just read and parse what is in there. if you want to change stuff, you should use the appropriate tool/API path, because then you need to take care of locking and concurrency.
