diff --git a/src/frontend/src/content/docs/app-host/eventing.mdx b/src/frontend/src/content/docs/app-host/eventing.mdx
index bafa25341..a61e6b1ab 100644
--- a/src/frontend/src/content/docs/app-host/eventing.mdx
+++ b/src/frontend/src/content/docs/app-host/eventing.mdx
@@ -113,6 +113,15 @@ builder.Eventing.Subscribe<AfterResourcesCreatedEvent>(
   callbacks like `onResourceReady`.
 </Aside>
 
+<Aside type="caution">
+  `Eventing.Subscribe<T>()` requires `T` to be a concrete event type.
+  Subscribing to an interface or abstract class throws an `ArgumentException`.
+  For `IDistributedApplicationEvent`, the exception message is
+  `Cannot subscribe to interface or abstract type 'IDistributedApplicationEvent'. Subscribe to a concrete event type instead.`
+  Use a concrete event type such as `BeforeStartEvent` or
+  `AfterResourcesCreatedEvent`.
+</Aside>
+
 When the AppHost is run, by the time the Aspire dashboard is displayed, you should see the following log output in the console:
 
 ```plaintext {2,12} data-disable-copy