Surface controller attribute requirement

Author: guardrex

aspnetcore/fundamentals/openapi/include-metadata.md

@@ -1,7 +1,7 @@
 ---
 title: Include OpenAPI metadata in an ASP.NET Core app
 author: captainsafia
-description: Learn how to add OpenAPI metadata in an ASP.NET Core app
+description: Learn how to add OpenAPI metadata in an ASP.NET Core app.
 ms.author: safia
 monikerRange: '>= aspnetcore-9.0'
 ms.custom: mvc
@@ -10,15 +10,19 @@ uid: fundamentals/openapi/include-metadata
 ---
 # Include OpenAPI metadata in an ASP.NET Core app
 
+This article explains how to add OpenAPI metadata in an ASP.NET Core app.
+
 ## Include OpenAPI metadata for endpoints
 
 :::moniker range=">= aspnetcore-10.0"
 
 ASP.NET collects metadata from the web app's endpoints and uses it to generate an OpenAPI document.
-In controller-based apps, metadata is collected from attributes like [`[EndpointDescription]`](xref:Microsoft.AspNetCore.Http.EndpointDescriptionAttribute), [`[HttpPost]`](xref:Microsoft.AspNetCore.Mvc.HttpPostAttribute),
-and [`[Produces]`](xref:Microsoft.AspNetCore.Mvc.ProducesAttribute).
-In minimal APIs, metadata can be collected from attributes, but may also be set by using extension methods
-and other strategies, such as returning <xref:Microsoft.AspNetCore.Http.TypedResults> from route handlers.
+
+In controller-based apps, metadata is collected from attributes such as [`[EndpointDescription]`](xref:Microsoft.AspNetCore.Http.EndpointDescriptionAttribute), [`[HttpPost]`](xref:Microsoft.AspNetCore.Mvc.HttpPostAttribute),
+and [`[Produces]`](xref:Microsoft.AspNetCore.Mvc.ProducesAttribute) when the controller has the [`[ApiController]` attribute](xref:Microsoft.AspNetCore.Mvc.ApiControllerAttribute).
+
+In minimal APIs, metadata can be collected from attributes but may also be set by using extension methods and other strategies, such as returning <xref:Microsoft.AspNetCore.Http.TypedResults> from route handlers.
+
 The following table provides an overview of the metadata collected and the strategies for setting it.
 
 | Metadata | Attribute | Extension method | Other strategies |