She was assured Khaos would do whatever it required for this. Hecate didn't need to know the details of everything. She'd get something out of it, and that was all that would matter.
Perhaps she'd warn Hermes and Peitho, but she hadn't done that for Medea, so it was probably unlikely she'd do it again.
"Contact me then when you wish to do it. I will prepare. And Olympus need not worry about just you with this. Often, it is prudent to remind them of their place."