When you use Counter Strike, do you draw the card right away or wait till after the chain?

When you play Counter Strike, you do not draw the card immediately. You must wait until the spell resolves.

According to the rules of Riftbound, spells are added to the chain as pending items and do not execute their effects until they resolve.

Sequence of events:

1. Play: You play Counter Strike, paying its costs. It is added to the chain.
2. Priority: After you play it, priority passes to your opponent, who has the opportunity to react to or counter the spell.
3. Resolution: If no further items are added to the chain, the chain resolves in reverse order (Last-In, First-Out). When Counter Strike resolves, you choose a unit to protect from the next instance of damage and then draw 1 card.

As noted in the Riftbound rules regarding chain resolution (Rule 340.1), the newest item on the chain resolves and executes its game effects in their entirety. You cannot draw the card before the spell resolves, and your opponent has a window to react to the spell while it is on the chain.

Note: I could not fully verify this ruling against the retrieved rules.