Tit for tat

Tit for tat is a Nash equilibrium strategy to Prisoners' Dilemma, and to many conflicts.

The key feature of any Nash equilibrium strategy is you have nothing to lose by announcing your strategy and nothing to gain by keeping it secret. It is by definition optimized against the best response your opponent may come up with against it.

Announcing your strategy, credibly, may induce the opponent to act differently than if the opponent does not know your strategy. In the case of Tit for Tat, your opponent will cooperate.