can I kicker Sphinx of Lost Truths after i see what cards i draw magic

[toffee]

can I kicker Sphinx of Lost Truths after i see what cards i draw

[Arix]

No, you have to choose whether or not to pay the kicker as you're casting it, long before it resolves, comes into play, its ability triggers, its ability resolves, and you draw your cards.

[toffee]

also lets say I dont have no cards in my hand and I didnt pay kicker. if i draw 3 cards and one of them is an instant can i cast it immediately before having to discard that way i dont discard it

[Arix]

No, you can't play anything until the abiltiy has fully finished resolving.