This house believes that enchantment should receive an ability low in enchantment, as follows:

ENCHANT (sigil) CONCEALMENT
Power: 1 (Any)
Channeling a little of your personal energy into a sigil, you may cause it to bend light around itself in such a way as to appear invisible to any not looking for it.

And a low level skill in discernment (at, like, novice) to do SIGILS, and see them.

My Manse looks so cluttered and ugly with all the keys and monoliths

I like being able to see my work lying around. ^^

I'd say put it in environment. That skill needs help.

Then don't conceal it