registerHook using the event name onOmnipackTransaction.
It is the only hook that knows which admin did it, so it is the one to use to log admin item spawns.
Payload
The admin inventory does not trigger
onItemTransferred, it only triggers this hook. This way the restrictions you write for your players are never applied to an admin spawning an item.itemNameFilter, itemTypeFilter, inventoryTypeFilter and inventoryFilter - the last two apply to inventoryId, so the omnipack itself is never what you filter on.
Examples
Log what admins spawn from the admin inventory
Log what admins spawn from the admin inventory
Stop admins from spawning a specific item
Stop admins from spawning a specific item
registerHook API, available filters, and return-value behavior.