User blog comment:Xilinoc/Everything but the Rain op. 10 - "Prinz von Licht"/@comment-5551986-20130516143856/@comment-8669536-20130516145556

I do't think Uryu has been an agent, at least not for the whole time. I think Captain Kurotsuchi would've known then considering he infected Uryu with his data-gathering bacterium, and I doubt Kurotsuchi would remove them. He would've known if Uryu had talked to any Quincies. But it is also possible that he removed the bacterium after the war with Aizen, or that Uryu or the Vandenreich found some way to remove them.

Another thing I came to think about is the possibility that Uryu has "joined" the Vandenreich now in order to let Kurotsuchi collect information about the Quincies.