Many hotels now add in the gratuity and service fees automatically. I either ask when I call in the order, or just ask the person who brings it, "is your tip in here already?" they are always honest about it, and I can choose to tip more if I feel so inclined.

Look at the bill before you sign it to see whether a tip is included. If not, the standard is the same (regardless of the meal) as it would be if you had the same meal in a restaurant.

Questions:

If the tip has been added automatically, how much was it?

Should the tip be the same as a waiter in a restaurant (15-20%) even though a waiter spends much more time and effort to serve you? Or should it reflect the time and effort of the server to wheel up the tray to you?

Virtually all hotels add the gratuity to the bill for room service, generally 15-18%.
I sometimes add a couple of bucks more if the service was particulary good, or the server was particularly friendly, but that is certainly not necessary. When you look at the bill, you will see the service charge added in. If you don't see it, ask (it also generally says right on the room service menu that such a charge will be added).

Usually the built-in tip is in the 15% range. Personally, I think it's splitting hairs to differentiate between the types of service. While the waiter in a restaurant may be more involved in your service, the room service waiter has a lot longer trip to your room!

I can't remember the last time I've seen room service gratuity at 15%. It is usually 18-22%.

I always throw in a couple of extra dollars because the waiter has to split that gratuity with the hotel. I figure I'm already paying $20 for a club sandwich so another $2 isn't going to bankrupt me.

Last time I use room service is at the Swissotel The Drake in NYC. They put 18% (I think, could be 15%) + $3 room service fee on the tab. So, no need to add any additional tip. Just sign the check and that's it.

You're probably right GoTravel. I haven't ordered room service in a while!

according to my hotel mgr friend, the service charge goes to hotel, and waiter/delivery person gets 100% of tip or gratuity charged on bill. She says many people are too embarrassed to ask, so tip twice. Waiters love it!