Here are some casting specs that were communicated to me by my agent this week (I'm paraphrasing for the sake of anonymity, but only slightly):
"Arrogant but clueless chef who thinks he's better than he is. Male, 30-50 years old, open on race. Good facial expressions, but not over the top. This is a real person, able to show emotions with the raise of an eyebrow, but stay away from extreme subtlety. The chef is a real person, but a heightened real person. National broadcast usage, plus cable, Internet, some print, and possible foreign broadcast. This character will become a spokesperson for a MAJOR worldwide brand, and the client is looking for strong actors who can convey the character consistently, and have that certain something extra that will make them the quintessential icon for the brand!"
Okay, so you know what the only usable part of that paragraph is? The first sentence, and practically nothing else. The ONLY thing I really need to know that will help me do a great job in the audition is that I'm an arrogant but clueless chef. The rest of it is either unhelpful (possibly even a hindrance), or else it's information no doubt intended to help you (the agent) do your job.
Gender and age range are tips to guide your submissions, and have little-to-no bearing on my prep work for the audition. The bit about "not too subtle, not too campy" is, at best, an indication to you that you should submit your strongest and most versatile talent. At worst, it's pretty darn confusing, and it's taken me literally years to realize that such pronouncements either indicate that the client doesn't know what they want, or that they're really bad at communicating what they want. The most useful sum-up I can make of this particular bit is "the client will know it when they see it" and "be prepared to do it different ways in the audition" (something most casting directors will encourage you to do anyway).
The rest of it, about what an icon this character is going to be (and how lucrative the gig will potentially be) is a downright hindrance for me. I mean, it's obviously going to be a great gig if I land it, but unless you have many personal experiences watching me rise above all others in the face of extreme pressure (not that auditions, opening nights, improv and other live performances aren't already extreme enough), why saddle me with that pressure for the audition? You want me to be relaxed. You want me to have fun. You want me to be playful. (Seriously, you do.) None of which come easier to me when I know that I'm going to miss out on fame and fortune if I screw up. Okay, I know there are exceptions — your favorite semi-retired client in Wisconsin who will only make the trip down to Chicago for "important" auditions, or the suburban parent who's on the fence between finding a babysitter or turning down the audition — but those are exceptions.
And, on an idealistic note, despite the fact that I recently bitched about low-usage commercials not being worth the effort, in point of fact I personally do actually feel that every role deserves the same investment of energy and dedication (which, I guess, means that you probably shouldn't tell me when a spot is going to get low usage either).
Oh, and by the way — just so you know, it's not like I keep my Extra Special Quintessential Something on reserve for some occasions and not for others. If I have it, trust me to bring it to every audition.
Really, I appreciate the openness with which you share information with your clients, and I can certainly edit out anything that I don't think is helpful, but I just thought I should tell you in case you'd never heard it before, and because it's taken me so long myself to realize what helps and what doesn't (which I don't really wish on anyone else in your stable).