So there may come a time when you may ask, “What is the sign of accomplishing this mahamudra practice, perhaps clairvoyance, perhaps levitation?”
The most important sign of realizing mahamudra is compassion.
The great Khenpo [Munsel] Rinpoche from whom I received teachings said things like clairvoyance, levitation, and so forth are not the qualities of mahamudra. The most important sign of realizing mahamudra is compassion. The more there is compassion in the mind, the more it enhances itself, and that is the sign of the arising of mahamudra realization.
– Garchen Rinpoche