diff --git a/src/lib/game.ts b/src/lib/game.ts
index dc78e59..decc2a0 100644
--- a/src/lib/game.ts
+++ b/src/lib/game.ts
@@ -23,6 +23,9 @@ export const DefaultRandom:RandomSource = {
   }
 }
 
+export interface ActionFactory {
+  next(game: Game): Action
+}
 
 // an action is in charge of the entire state transition
 export interface Action {