More on the series question

A good point an editor brought up in the chat last night: she'd, you know, really kind of like to know right away if the author envisioned the work as a series.

If you don't tell your agent this until after he/she begins sending your work out, you could put him/her in a really awkward position.

Okay, imagine this. I've just sent out a manuscript. The author writes, "GK, GK! I have a brilliant idea! This is a series! This is only a series! It cannot be anything but a series! Go tell the editors!"

I will then probably:

1. Panic
2. Consider whether the author is just kidding, like the "And my next book is about vampires! Just kidding!" kind of way/if I think it would be better for the work to be a stand-alone or a series. If I think the author just wants a multi-book deal but that the work will not be as good editorially in multiple parts, that's a separate discussion. But, assuming it would work as a series, I'd...
3. Get mad at author.
4. Consider the best way of contacting editors. 

Step four is the hardest: I'd look rather dumb if I try the "Hi! So, funny story. My author didn't tell me until now that he/she thinks this is a series! Funny, huh? So this agent walks into a bar..."--which makes it look like I didn't bother to ask really important questions, and/or the author cannot be trusted, and/or this project is pretty much a train wreck waiting to happen. 

It's not a good impression. It makes me look bad, and the editors will remember this in the future. In other words, it will hurt me for this project, and it may hurt my relationships with these editors long-term. 

I've never (knock on a forest) had this happen, but this is the sort of thing that will make agents wake up in the middle of the night in a cold sweat. Yeah. The stuff of agent nightmares.

I could wait until an editor is interested and then float the idea of a series. There are a number of things I could do that would go a little better.

But the bottom line is that this possibility is so incredibly uncomfortable for agents, that I really think you should always err on the side of telling your agent (once they're yours) everything. 

If you don't, it'd be kind of like being on trial for murder, and "forgetting" to tell your lawyer that there are, I don't know, gloves that may or may not fit just waiting to be discovered--thus leaving your agent without a rebuttal in a really rather uncomfortable situation. Had you just told your agent everything immediately, he/she could have found a way to present/respond to the information in the best honest way possible.

Yeah. Just don't hide things from your agent. It's poor form, and it will hurt you in the long run.