How do these two abilities interact?
A bard adds half his class level (minimum 1) to all Knowledge skill checks and may make all Knowledge skill checks untrained.
A master spy gives the appearance of knowing more than she actually does. Starting at 3rd level, she can make untrained Knowledge and Profession checks pertaining to her cover or assumed identity as if she were trained and gains a bonus equal to half her level on these checks. For example, a master spy masquerading as a noblewoman can make untrained Knowledge (history) checks about the kingdom and Knowledge (nobility) checks about its noble and royal families as if she were trained, but she cannot make untrained Knowledge (nature) skill checks to identify herbs.
I'd imagine you'd add half your bard level and half your master spy level (if it applied) to the check.
I guess I'm just unsure because the Master Spy ability suggests it isn't REAL knowledge, just good improvisation and acting, whereas the bard is suppose to really know it. The sad thing is training knowledge checks I presume makes Superficial Knowledge useless.