diff --git a/src/Microsoft.AspNet.Mvc.Core/Filters/ActionFilterAttribute.cs b/src/Microsoft.AspNet.Mvc.Core/Filters/ActionFilterAttribute.cs
index b342870270..b84c226fb8 100644
--- a/src/Microsoft.AspNet.Mvc.Core/Filters/ActionFilterAttribute.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/Filters/ActionFilterAttribute.cs
@@ -3,6 +3,7 @@ using System.Threading.Tasks;
 
 namespace Microsoft.AspNet.Mvc
 {
+    // TODO: Consider making this user a before and after pattern instead of just Invoke, same for all other filter attributes.
     [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true, Inherited = true)]
     public abstract class ActionFilterAttribute : Attribute, IActionFilter, IFilter
     {
diff --git a/src/Microsoft.AspNet.Mvc.Core/Filters/ActionFilterEndPoint.cs b/src/Microsoft.AspNet.Mvc.Core/Filters/ActionFilterEndPoint.cs
index 11c580bbfd..d14b40273c 100644
--- a/src/Microsoft.AspNet.Mvc.Core/Filters/ActionFilterEndPoint.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/Filters/ActionFilterEndPoint.cs
@@ -4,6 +4,7 @@ using System.Threading.Tasks;
 
 namespace Microsoft.AspNet.Mvc.Filters
 {
+    // This one lives in the Filters namespace, and only intended to be consumed by folks that rewrite the action invoker.
     public class ReflectedActionFilterEndPoint : IActionFilter
     {
         private readonly Func<object[], Task<object>> _coreMethodInvoker;
diff --git a/src/Microsoft.AspNet.Mvc.Core/Filters/ActionResultFilterEndPoint.cs b/src/Microsoft.AspNet.Mvc.Core/Filters/ActionResultFilterEndPoint.cs
index 32ddd87cbd..06836cec5a 100644
--- a/src/Microsoft.AspNet.Mvc.Core/Filters/ActionResultFilterEndPoint.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/Filters/ActionResultFilterEndPoint.cs
@@ -3,6 +3,7 @@ using System.Threading.Tasks;
 
 namespace Microsoft.AspNet.Mvc.Filters
 {
+    // This one lives in the Filters namespace, and only intended to be consumed by folks that rewrite the action invoker.
     public class ActionResultFilterEndPoint : IActionResultFilter
     {
         public async Task Invoke(ActionResultFilterContext context, Func<Task> next)
diff --git a/src/Microsoft.AspNet.Mvc.Core/Filters/AuthorizationFilterEndPoint.cs b/src/Microsoft.AspNet.Mvc.Core/Filters/AuthorizationFilterEndPoint.cs
index 27337e14c9..910cfe0479 100644
--- a/src/Microsoft.AspNet.Mvc.Core/Filters/AuthorizationFilterEndPoint.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/Filters/AuthorizationFilterEndPoint.cs
@@ -3,6 +3,7 @@ using System.Threading.Tasks;
 
 namespace Microsoft.AspNet.Mvc.Filters
 {
+    // This one lives in the Filters namespace, and only intended to be consumed by folks that rewrite the action invoker.
     public class AuthorizationFilterEndPoint : IAuthorizationFilter
     {
         public bool EndPointCalled { get; private set; }
diff --git a/src/Microsoft.AspNet.Mvc.Core/Filters/DefaultFilterProvider.cs b/src/Microsoft.AspNet.Mvc.Core/Filters/DefaultFilterProvider.cs
index 77a8251174..0fa858f778 100644
--- a/src/Microsoft.AspNet.Mvc.Core/Filters/DefaultFilterProvider.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/Filters/DefaultFilterProvider.cs
@@ -3,7 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using Microsoft.AspNet.DependencyInjection;
 
-namespace Microsoft.AspNet.Mvc
+namespace Microsoft.AspNet.Mvc.Filters
 {
     public class DefaultFilterProvider : INestedProvider<FilterProviderContext>
     {
diff --git a/src/Microsoft.AspNet.Mvc.Core/Filters/ExceptionFilterContext.cs b/src/Microsoft.AspNet.Mvc.Core/Filters/ExceptionFilterContext.cs
index 8beab4563d..ebdebbd22f 100644
--- a/src/Microsoft.AspNet.Mvc.Core/Filters/ExceptionFilterContext.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/Filters/ExceptionFilterContext.cs
@@ -2,6 +2,8 @@
 
 namespace Microsoft.AspNet.Mvc
 {
+    // TODO: For now we have not implemented the ExceptionFilter pipeline, leaving this in until we decide if we are going
+    // down this path or implementing an ExceptionFilterAttribute being all three filter types with a higher scope.
     public class ExceptionFilterContext
     {
         public ExceptionFilterContext(ActionContext actionContext, Exception exception)
diff --git a/src/Microsoft.AspNet.Mvc.Core/ReflectedActionDescriptorProvider.cs b/src/Microsoft.AspNet.Mvc.Core/ReflectedActionDescriptorProvider.cs
index 22253e9e99..26dfd5b058 100644
--- a/src/Microsoft.AspNet.Mvc.Core/ReflectedActionDescriptorProvider.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/ReflectedActionDescriptorProvider.cs
@@ -127,6 +127,7 @@ namespace Microsoft.AspNet.Mvc
             return ad;
         }
 
+        // Merge filters, filters with the same order are prioritzed by origin action executes ahead of controller.
         private List<IFilter> MergeSorted(IFilter[] filtersFromAction, IFilter[] filtersFromController)
         {
             var list = new List<IFilter>();
diff --git a/src/Microsoft.AspNet.Mvc.Core/ReflectedActionInvoker.cs b/src/Microsoft.AspNet.Mvc.Core/ReflectedActionInvoker.cs
index 2f659370e5..9fb91c9a70 100644
--- a/src/Microsoft.AspNet.Mvc.Core/ReflectedActionInvoker.cs
+++ b/src/Microsoft.AspNet.Mvc.Core/ReflectedActionInvoker.cs
@@ -67,14 +67,13 @@ namespace Microsoft.AspNet.Mvc
 
                     var authZFilters = context.AuthorizationFilters;
 
-                    bool authZPassed;
                     if (authZFilters != null && authZFilters.Count > 0)
                     {
                         var authZEndPoint = new AuthorizationFilterEndPoint();
                         authZFilters.Add(authZEndPoint);
+
                         var authZContext = new AuthorizationFilterContext(_actionContext);
-                        var authZPipeline = new FilterPipelineBuilder<AuthorizationFilterContext>(authZFilters,
-                            authZContext);
+                        var authZPipeline = new FilterPipelineBuilder<AuthorizationFilterContext>(authZFilters, authZContext);
 
                         await authZPipeline.InvokeAsync();
 
@@ -86,7 +85,8 @@ namespace Microsoft.AspNet.Mvc
                         }
                         else
                         {
-                            actionResult = authZContext.ActionResult ?? new HttpStatusCodeResult(401);                            
+                            // User cleaned out the result but we failed or short circuited the end point.
+                            actionResult = authZContext.ActionResult ?? new HttpStatusCodeResult(401);
                         }
                     }
                     else
@@ -112,7 +112,7 @@ namespace Microsoft.AspNet.Mvc
 
                         await actionFilterPipeline.InvokeAsync();
 
-                        actionResult = (IActionResult)actionFilterContext.Result;
+                        actionResult = actionFilterContext.Result;
                     }
                 }
             }
diff --git a/src/Microsoft.AspNet.Mvc/MvcServices.cs b/src/Microsoft.AspNet.Mvc/MvcServices.cs
index b5ed63ec43..f191172f4e 100644
--- a/src/Microsoft.AspNet.Mvc/MvcServices.cs
+++ b/src/Microsoft.AspNet.Mvc/MvcServices.cs
@@ -4,6 +4,7 @@ using Microsoft.AspNet.ConfigurationModel;
 using Microsoft.AspNet.DependencyInjection;
 using Microsoft.AspNet.DependencyInjection.NestedProviders;
 using Microsoft.AspNet.FileSystems;
+using Microsoft.AspNet.Mvc.Filters;
 using Microsoft.AspNet.Mvc.ModelBinding;
 using Microsoft.AspNet.Mvc.Razor;
 using Microsoft.Net.Runtime;