The feat Touch of Serenity reads:
Spoiler:
You must declare that you are using this feat before you make your attack roll (thus a failed attack roll ruins the attempt). On a successful hit, the attack deals no damage and bestows no other effect or condition, but the target cannot cast spells or attack (including attacks of opportunity and attacks as immediate actions) for 1 round unless it succeeds on a Will saving throw with a DC of 10 + 1/2 your character level + your Wisdom modifier. You may attempt a touch of serenity once per day for every four levels you have attained (but see Special), and no more than once per round.
Even though "touch" is in the name it never specifies that it's a touch attack - does that mean you make it vs. full AC?
I'd think it is against full AC as it reads just like Stunning Fist (with the obvious exception of what it actually does) and is a possible replacement for Stunning Fist.
Also since it doesn't specify touch, it definitely seems like it wouldn't.
