Where would I find the description for the stored procedures used for UCCX?
If you want to create custom reports you do need to access the DB directly and you do need to create your own custom Store procedures.
Reviewing the existing ones (and creating modified versions of them) is the easiest way to learn how to do this and is what I have done for a number of custom reports.
By using AGS Server Studio (free evaluation version), you can connect, view and take a backup of the standard store procedures used for reporting. I do not see why Cisco do not publish this, but at the same time, it is easy to get this info yourself if necessary.
This approach is documented by Cisco in the below URL: