Improved Conceal SpellSource Ultimate Intrigue pg. 84
You can conceal the mightiest spells in the subtlest fashions.
Prerequisites: Conceal Spell, Deceitful, Bluff 5 ranks, Disguise 5 ranks, Sleight of Hand 10 ranks, ability to cast 3rd-level spells or use a 3rd-level spell-like ability.
Benefit: When you use Conceal Spell, creatures no longer gain a bonus equal to the level of the spell or spell-like ability on their checks to notice the hidden spell.
Normal: Creatures attempting to notice a spell hidden with Conceal Spell gain a bonus equal to the level of the spell or spell-like ability on their Perception, Sense Motive, and Spellcraft checks.