When tap a unit and play Meditation with Temporal Portal, do I draw 4 or 3?

To determine how many cards you draw, we must look at how Meditation and Temporal Portal interact.

Ruling

You draw 3 cards total.

Reasoning

1. Temporal Portal's Effect: When you activate Temporal Portal, it gives the next spell you play this turn the [Repeat] keyword equal to its cost. Since Meditation costs 2 energy, you have the option to pay an additional 2 energy to repeat its effect.
2. Meditation's Effect: Meditation has two outcomes based on whether you pay the additional cost of exhausting a friendly unit:
   • If you exhaust a unit: Draw 2.
   • If you do not exhaust a unit: Draw 1.
3. The Sequence:
   • You activate Temporal Portal (exhausting it) to grant your next spell [Repeat] (cost 2).
   • You play Meditation. You choose to exhaust a friendly unit to pay its additional cost.
   • First Resolution: Meditation resolves. Because you exhausted a unit, you draw 2 cards.
   • Second Resolution (Repeat): You pay the 2 energy cost to trigger the [Repeat] effect granted by the Temporal Portal. You resolve the effect of Meditation again. Since you have already paid the cost of exhausting a unit (or if you choose not to exhaust another unit for the second resolution), you draw 1 card (or 2 if you exhaust a second unit).

Note on the "3 cards" total: If you exhaust one unit for the initial cast of Meditation, you draw 2. When you trigger the [Repeat] effect, you are repeating the effect of the spell. Since the cost of exhausting a unit was an "additional cost to play" the spell, that cost is not repeated. Therefore, the repeated effect resolves as if you did not exhaust a unit, drawing you 1 additional card, for a total of 3.

This is my interpretation based on the mechanics of [Repeat] and additional costs. No official FAQ exists for this specific interaction.