diff --git a/packages/docs/content/api.mdx b/packages/docs/content/api.mdx
index b7bf366ad..556cdbcd0 100644
--- a/packages/docs/content/api.mdx
+++ b/packages/docs/content/api.mdx
@@ -1157,6 +1157,18 @@ Dog.def.shape.age; // => number schema
 </Tab>
 </Tabs>
 
+<Callout>
+  When a schema is transformed, the `shape` is accessed from the `in` or `out` key:
+
+  ```ts
+  const Puppy = Dog.transform(({ age }) => age < 1);
+  Puppy.in.shape.name; // => string schema
+  Puppy.in.shape.age; // => number schema
+  Puppy.out; // => boolean schema
+  ```
+
+</Callout>
+
 ### `.keyof()`
 
 To create a `ZodEnum` schema from the keys of an object schema: