[SOLVED] what would be a useful role for a pure api get

The PVEAuditor role is intended for that purpose. If you want to limit access to VMs and nodes (excluding storage, pools and access control) you can give the user access to only /vms and /nodes. For example:
Code:
# pveum aclmod /vms --roles PVEAuditor --users audit@pve
# pveum aclmod /nodes --roles PVEAuditor --users audit@pve