The Orb of Detection confers automatic searching while carried, with a 100% chance of succeeding.

The Orb of Detection confers passive detect unseen: every few turns when carried it triggers the effect of zapping a wand of secret door detection for free.

Invoking artifacts for invisibility makes you visible again if you are already permanently invisible. Also, move the Orb of Detection’s invoke invisibility ability to some lesser artifact because it’s a lame power for a quest artifact.

The Orb of Detection can detect the presence (but not location) of artifacts on the level. Possibly this is an Archeologist-only power.

The Orb of Detection grants automatic searching in a region of radius 2.