I agree with Irlfiteclub, Koshka really doesn't need Clockwork because of her basic attacks decreasing cooldown. I rarely run out of energy mid-game onward. The best way to solve any energy dilemmas is to just buy 2-4 Halcyon Potions and pop them whenever you are a tad low. Also, Eve grants you that extra energy regen and energy cap, so in the end, Clockwork is a seemingly waste of a slot and gold.

I definitely recommend permanently placing in a defensive item (like Crucble) instead of Clockwork. I would also rush Crucible at least right after you get your first complete attack item.

Good Luck!

That would make you faster but your mana is really important

You could replace Clockwork with Travel/Journey Boots, as Koshka's abilities already cool down pretty fast. And Koshka will need boots to escape from an ambush or whatever.