Historical Rules · 5 February 2021
Rule 811.5
Official source text from the 5 February 2021 Rules release
In the Alternating Teams variant, a team’s resources (cards in hand, mana, and so on) are not shared. Teammates can’t review each other’s hands unless they are sitting next to each other. Teammates may discuss strategies at any time. Teammates can’t manipulate each other’s cards or permanents.