Modeling a “Bob” in Dresden Files

I’m running a Dresden Files game, and I think my PCs need a Bob. Because I need a mouthpiece and exposition engine.

But the description of Bob in Our World is skimpy at best, equating him to just a Lore check at +5.

I’m comfortable creating the story of our Bob equivalent. But how does the relationship with the PCs get modeled in-game? And has anyone used the existing Powers / Skills to create something like this in more detail?

My thought was to introduce the artifact / character and then allow the PCs to swap an existing Aspect for one related to it at the next opportunity. That Aspect will let the players use our “Bob” for Declarations, for effects, etc..

And if they don’t, then I have all the control over Bob. I say when he speaks, and when he won’t. What he knows and what he doesn’t.

Bottom line: If they don’t incorporate our Bob into their Aspects, then he’s my plot device, my mouthpiece. If they do, he becomes a way for them to tell their stories and solve their problems.

Sound fair?