Would this work for a SpellThief?

[TheDarkSaint]

I'm curious if the following would work as I'm thinking it would work on a Spellthief character.

Spellthief (6th level)
Feats: Improved Initiative, Sudden Silent, Sudden Still and Eschew Materials
Flaws: Vulnerable

Spells:
1st: Nerveskitter, Distract Assailant, Critical Strike

With Imp In and Nerveskitter, I think I'll be going first. Distract and Critical Strike are both swift action spells, so I can use them before an attack for sneak attack damage.

My question is, if I made them silent, still and with no materials, would I still need to cast them defensively to keep from provoking an opportunity of attack?

Right now, she's an NPC. The DM in me says "yes" but i can see the surprise value and can see a player argument of "no".

What would you guys rule?

[Lord Haart]

My question is, if I made them silent, still and with no materials, would I still need to cast them defensively to keep from provoking an opportunity of attack?

Yes. Just as a psion needs to manifest defensively, despite not having any components at all.

Attacks of opportunity for that stuff don't work like "Thog sees funny wizard is casting a spell, Thog has rights to smash funny wizard!". Rather, it works kinda like "Thog sees funny wizard getting distracted not enough to get denied dex to AC, but enough to possibly get hit one more time by the weapon-flailing-all-around-Thog's-threatened-area Thog is supposedly doing all the time on his off-turn".

[TheDarkSaint]

I suppose if combat hadn't started, I could rule that all the spell hiding could qualify her for a surprise round.

[Mr Adventurer]

Swift action spells don't provoke an AoO, so you don't need to cast them defensively.

You can also only cast one per round.

[nedz]

Spellthieves effectively cast spells as a Sorcerer. I'm not aware of any rule which states that Sudden Metamagic feats don't increase the casting time so they may no longer be swift actions. This would cause them to provoke.