diff --git a/.agents/rules/python.md b/.agents/rules/python.md
index 22221fe3a1..200295e650 100644
--- a/.agents/rules/python.md
+++ b/.agents/rules/python.md
@@ -9,3 +9,7 @@
 * Use direct attribute access (e.g. `args.foo`) on `argparse.Namespace` with
   well-defined shapes. Avoid defensive `getattr()`.
 
+## TypedDict
+* **External Objects**: When defining a `TypedDict` for an external object,
+  link to its definition in the docstring.
+