diff --git a/Modules/OpenApi/Discovery/Extensions.cs b/Modules/OpenApi/Discovery/Extensions.cs
deleted file mode 100644
index 8012511c..00000000
--- a/Modules/OpenApi/Discovery/Extensions.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-namespace GenHTTP.Modules.OpenApi.Discovery;
-
-internal static class Extensions
-{
-
-    internal static bool MightBeNull(this Type type)
-    {
-        if (type.IsClass)
-        {
-            return true;
-        }
-
-        return Nullable.GetUnderlyingType(type) != null;
-    }
-
-}
diff --git a/Modules/OpenApi/Discovery/MethodHandlerExplorer.cs b/Modules/OpenApi/Discovery/MethodHandlerExplorer.cs
index f232e331..3952acfa 100644
--- a/Modules/OpenApi/Discovery/MethodHandlerExplorer.cs
+++ b/Modules/OpenApi/Discovery/MethodHandlerExplorer.cs
@@ -30,7 +30,7 @@ public void Explore(IHandler handler, List<string> path, OpenApiDocument documen
                 }
             }
 
-            var pathItem = GetPathItem(document, path, methodHandler.Operation);
+            var pathItem = OpenApiExtensions.GetPathItem(document, path, methodHandler.Operation);
 
             foreach (var method in methodHandler.Configuration.SupportedMethods)
             {
@@ -112,44 +112,6 @@ public void Explore(IHandler handler, List<string> path, OpenApiDocument documen
         }
     }
 
-    private static OpenApiPathItem GetPathItem(OpenApiDocument document, List<string> path, Operation operation)
-    {
-        var stringPath = BuildPath(operation.Path.Name, path);
-
-        if (document.Paths.TryGetValue(stringPath, out var existing))
-        {
-            return existing;
-        }
-
-        var newPath = new OpenApiPathItem();
-
-        document.Paths.Add(stringPath, newPath);
-
-        return newPath;
-    }
-
-    private static string BuildPath(string name, List<string> pathParts)
-    {
-        var builder = new StringBuilder("/");
-
-        if (pathParts.Count > 0)
-        {
-            builder.Append(string.Join('/', pathParts));
-            builder.Append('/');
-        }
-
-        if (name.Length > 0 && name[0] == '/')
-        {
-            builder.Append(name[1..]);
-        }
-        else
-        {
-            builder.Append(name);
-        }
-
-        return builder.ToString();
-    }
-
     private static OpenApiParameterKind MapArgumentType(OperationArgumentSource source) => source switch
     {
         OperationArgumentSource.Path => OpenApiParameterKind.Path,
diff --git a/Modules/OpenApi/Discovery/OpenApiExtensions.cs b/Modules/OpenApi/Discovery/OpenApiExtensions.cs
new file mode 100644
index 00000000..2a4c7be7
--- /dev/null
+++ b/Modules/OpenApi/Discovery/OpenApiExtensions.cs
@@ -0,0 +1,58 @@
+using System.Text;
+using GenHTTP.Modules.Reflection.Operations;
+using NSwag;
+
+namespace GenHTTP.Modules.OpenApi.Discovery;
+
+public static class OpenApiExtensions
+{
+
+    public static bool MightBeNull(this Type type)
+    {
+        if (type.IsClass)
+        {
+            return true;
+        }
+
+        return Nullable.GetUnderlyingType(type) != null;
+    }
+
+    public static OpenApiPathItem GetPathItem(OpenApiDocument document, List<string> path, Operation operation)
+    {
+        var stringPath = BuildPath(operation.Path.Name, path);
+
+        if (document.Paths.TryGetValue(stringPath, out var existing))
+        {
+            return existing;
+        }
+
+        var newPath = new OpenApiPathItem();
+
+        document.Paths.Add(stringPath, newPath);
+
+        return newPath;
+    }
+
+    public static string BuildPath(string name, List<string> pathParts)
+    {
+        var builder = new StringBuilder("/");
+
+        if (pathParts.Count > 0)
+        {
+            builder.Append(string.Join('/', pathParts));
+            builder.Append('/');
+        }
+
+        if (name.Length > 0 && name[0] == '/')
+        {
+            builder.Append(name[1..]);
+        }
+        else
+        {
+            builder.Append(name);
+        }
+
+        return builder.ToString();
+    }
+
+}
diff --git a/Modules/OpenApi/Handler/OpenApiConcern.cs b/Modules/OpenApi/Handler/OpenApiConcern.cs
index 345c0788..079f59cb 100644
--- a/Modules/OpenApi/Handler/OpenApiConcern.cs
+++ b/Modules/OpenApi/Handler/OpenApiConcern.cs
@@ -6,9 +6,11 @@
 
 namespace GenHTTP.Modules.OpenApi.Handler;
 
+internal record ReturnDocument(OpenApiDocument Document, ulong Checksum);
+
 public sealed class OpenApiConcern : IConcern
 {
-    private OpenApiDocument? _Cached;
+    private ReturnDocument? _Cached;
 
     #region Initialization
 
@@ -97,7 +99,7 @@ private IResponse GetDocument(IRequest request, OpenApiFormat format)
                       .Build();
     }
 
-    private OpenApiDocument Discover(IRequest request, ApiDiscoveryRegistry registry)
+    private ReturnDocument Discover(IRequest request, ApiDiscoveryRegistry registry)
     {
         if (EnableCaching && _Cached != null)
         {
@@ -126,12 +128,15 @@ private OpenApiDocument Discover(IRequest request, ApiDiscoveryRegistry registry
 
         if (EnableCaching)
         {
-            _Cached = document;
+            _Cached = new (document, GetChecksum(document));
+            return _Cached;
         }
 
-        return document;
+        return new (document, GetChecksum(document));
     }
 
+    private static ulong GetChecksum(OpenApiDocument document) => (ulong)document.ToJson().GetHashCode();
+
     #endregion
 
 }
diff --git a/Modules/OpenApi/Handler/OpenApiContent.cs b/Modules/OpenApi/Handler/OpenApiContent.cs
index daab147d..af2d45f7 100644
--- a/Modules/OpenApi/Handler/OpenApiContent.cs
+++ b/Modules/OpenApi/Handler/OpenApiContent.cs
@@ -9,7 +9,7 @@ internal class OpenApiContent : IResponseContent
 
     #region Initialization
 
-    internal OpenApiContent(OpenApiDocument document, OpenApiFormat format)
+    internal OpenApiContent(ReturnDocument document, OpenApiFormat format)
     {
         Document = document;
         Format = format;
@@ -21,7 +21,7 @@ internal OpenApiContent(OpenApiDocument document, OpenApiFormat format)
 
     public ulong? Length => null;
 
-    private OpenApiDocument Document { get; }
+    private ReturnDocument Document { get; }
 
     private OpenApiFormat Format { get; }
 
@@ -29,17 +29,17 @@ internal OpenApiContent(OpenApiDocument document, OpenApiFormat format)
 
     #region Functionality
 
-    public ValueTask<ulong?> CalculateChecksumAsync() => new((ulong)Document.ToJson().GetHashCode());
+    public ValueTask<ulong?> CalculateChecksumAsync() => new(Document.Checksum);
 
     public async ValueTask WriteAsync(Stream target, uint bufferSize)
     {
         if (Format == OpenApiFormat.Json)
         {
-            await target.WriteAsync(Encoding.UTF8.GetBytes(Document.ToJson()));
+            await target.WriteAsync(Encoding.UTF8.GetBytes(Document.Document.ToJson()));
         }
         else
         {
-            await target.WriteAsync(Encoding.UTF8.GetBytes(Document.ToYaml()));
+            await target.WriteAsync(Encoding.UTF8.GetBytes(Document.Document.ToYaml()));
         }
     }
 
diff --git a/Testing/Acceptance/Modules/OpenApi/InfrastructureTests.cs b/Testing/Acceptance/Modules/OpenApi/InfrastructureTests.cs
index 1020d958..bf406bee 100644
--- a/Testing/Acceptance/Modules/OpenApi/InfrastructureTests.cs
+++ b/Testing/Acceptance/Modules/OpenApi/InfrastructureTests.cs
@@ -14,7 +14,7 @@ public async Task TestContentIsPassed()
     {
         var api = Inline.Create()
                         .Get("/some-path", () => "Hello World")
-                        .Add(ApiDescription.Create());
+                        .AddOpenApi();
 
         using var host = TestHost.Run(api);
 
@@ -43,9 +43,10 @@ private async Task<int> RunCachingTest(bool cacheEnabled)
 
         using var host = TestHost.Run(api);
 
-        await host.GetResponseAsync("/openapi.json");
-        await host.GetResponseAsync("/openapi.json");
+        AssertX.Contains("\"openapi\"", await (await host.GetResponseAsync("/openapi.json")).GetContentAsync());
+        AssertX.Contains("openapi:", await (await host.GetResponseAsync("/openapi.yaml")).GetContentAsync());
 
         return counter;
     }
+
 }
diff --git a/Testing/Acceptance/TestExtensions.cs b/Testing/Acceptance/TestOpenApiExtensions.cs
similarity index 91%
rename from Testing/Acceptance/TestExtensions.cs
rename to Testing/Acceptance/TestOpenApiExtensions.cs
index 1c664932..51f423d6 100644
--- a/Testing/Acceptance/TestExtensions.cs
+++ b/Testing/Acceptance/TestOpenApiExtensions.cs
@@ -3,7 +3,7 @@
 
 namespace GenHTTP.Testing.Acceptance;
 
-public static class TestExtensions
+public static class TestOpenApiExtensions
 {
 
     public static IHandlerBuilder<HandlerBuilder> Wrap(this IHandler handler) => new HandlerBuilder(handler);