Project workspaces are awesome. There I have said it. But one thing that has always frustrated me and other users is how hard it is to determine what project the workspace is linked to. The only reliable way of determining the ProjectUID is to look in the Property Bag of the site where Project Server stores the association. There are a couple of tricks that will let you find out the ProjectUID, one of them being developing a custom web part like I did a while back, or using the CSOM in 2013 as Giles Hamson posted a while ago,

A couple of months ago, I was wondering if there was a simple way to show project reports automatically within a project workspace. The problem seems quite simple at first, all you need to do is work out which workspace you are in, then pass that value into the Reporting Services viewer web part as a web part connection. After a bit of experimenting with the out of the box web part filter providers, jQuery and other black magic, I quickly came to the conclusion that this wasn’t going to be an easy ask and so cracked open my old friend, Visual Studio 2010.