Each user who performs SharePoint configuration management operations via Stages needs a SharePoint user account. The user will be prompted once for his SharePoint credentials when they are needed. After successful authentication, Stages will reuse these credentials for subsequent operations, until an authentication attempt fails.
Besides the individual user accounts, one SharePoint account is needed by Stages for administrative purposes. This account needs at least a permission level of Read. Additionally a permission level of Override Check-Out is required if the Stages root account shall be able to unlock files which have been locked exclusively by other users.