X2 / S2 switch — one sentence operation, 0/40 → 37/40

The bare configuration cooperated 0.000 at every registered continuation probability. X2 decomposed the prompt into six spans and ran forward/reverse replacement ladders. The selected operation replaced and repositioned “After every round there is a {deltaPct}% chance the session continues with another round” with “At the end of each round there is a {deltaPct}% chance that the session goes on for one more round.” Held-out confirmation moved cooperation from 0/40 to 37/40.

Wording and position were one atomic operation, so the design does not separate them. The effect is specific to representing repeated interaction — the registered one-shot D1 wording main effect was a null (+0.0063, Holm-adjusted p=1.00).