Hello there,

Here is my take on Mirage Prime on any boring/endless missions like ESO or any Survival/Defense or even Arbitration.
The main think is to do a lot of damage with the least effort. Do do so I replaced her Prism with Dispensary for free Energy replenish.

Primary damage skill here is Sleight of Hand with augment [Explosive Legerdemain].

To help with very low Energy Efficiency we got Arcane Energize, [Primed Flow], [Preparation] and Dispensary skill.

Dispensary also replenish her HP and ammo if you ever need to use any range weapon.

To help with her low eHP I gave her Arcane Resistance in case those stupid Toxin Clouds gets her. You can replace that Arcane with whatever you want.

Also, you can try this build with only two regular Forma:

Enjoy, THeMooN85