diff --git a/src/Control/Monad/Logic/Trans.purs b/src/Control/Monad/Logic/Trans.purs
index d1ed097..f0f5208 100644
--- a/src/Control/Monad/Logic/Trans.purs
+++ b/src/Control/Monad/Logic/Trans.purs
@@ -27,7 +27,7 @@ unSFKT (SFKT f) = f
 runSFKT :: forall a m. Applicative m => SFKT m a -> m (List a)
 runSFKT (SFKT f) = f (map <<< (:)) (pure Nil)
 
-runSFKTOnce :: forall a m. MonadPlus m => SFKT m a -> m a
+runSFKTOnce :: forall a m. Alternative m => SFKT m a -> m a
 runSFKTOnce (SFKT f) = f ((<|>) <<< pure) empty
 
 instance Functor (SFKT m) where