I feel like there is an easy answer to this question, and somewhere I am
missing something simple, how to pass through some type of generic
credential to the middle tier.

I have an environment of a fully populated Active Directory tree with
users. I am creating workstation objects through ZFD agent importation.
I need the agent on the workstation for the creation of the
workstations, but don't want to have the end users bothered by a middle
tier login. Sounds simple enough? What am I missing?