diff --git a/lib/ash/resource/preparation/preparation.ex b/lib/ash/resource/preparation/preparation.ex
index caca09c49..7b2458a58 100644
--- a/lib/ash/resource/preparation/preparation.ex
+++ b/lib/ash/resource/preparation/preparation.ex
@@ -5,6 +5,8 @@ defmodule Ash.Resource.Preparation do
   `c:init/1` is defined automatically by `use Ash.Resource.Preparation`, but can be implemented if you want to validate/transform any
   options passed to the module.
 
+  `c:supports/1` is also required and returns a list containing any or all of the following: `[Ash.Changeset, Ash.Query, Ash.ActionInput]` based on what your `c:prepare/3` implementation supports
+
   The main function is `c:prepare/3`. It takes the query, any options that were provided
   when this preparation was configured on a resource, and the context, which currently only has
   the actor.