Index -> Glossary -> Response

Response

Check all requirements to perform an action (such as playing a card) before paying its costs. Some cards require you to twilight tokens in the twilight pool, for example, and so there must be the required number of twilight tokens in the pool before the card is played.Response is a timing word that means that you may play an event (or use a special ability) whenever the situation described in its game text happens. After all required actions to a particular trigger have resolved, players may perform response actions responding to that same trigger.

Sometimes a response action interrupts another action to cancel it before it resolves. When this happens, that other action does not have its effect, but its costs and requirements are still paid. You may respond more than once to the same situation