Trickster ACF for Spellthief - Do I cast with Charisma? Or Use Int?

[Leathros]

Trickster ACF for Spellthief says you "cast spells as a bard of your Spellthief lvl", but it doesen't stand if you still use your INT as your core ability for casting.

[ZeroSpace9000]

...Well, both Spellthief and Bard use Charisma for casting. I'm pretty sure it would be CHA then. Not sure where exactly you got INT from.