diff --git a/lib/reactor/dsl/group.ex b/lib/reactor/dsl/group.ex
index 82fb568..5c4928e 100644
--- a/lib/reactor/dsl/group.ex
+++ b/lib/reactor/dsl/group.ex
@@ -52,7 +52,7 @@ defmodule Reactor.Dsl.Group do
           """
         ],
         after_all: [
-          type: {:mfa_or_fun, 3},
+          type: {:mfa_or_fun, 1},
           required: true,
           doc: """
           The after function. See `Reactor.Step.Group` for more information.