diff --git a/src/Core/Extensions/Basic.cs b/src/Core/Extensions/Basic.cs
index 359faf8..562b5a5 100644
--- a/src/Core/Extensions/Basic.cs
+++ b/src/Core/Extensions/Basic.cs
@@ -333,7 +333,7 @@ internal static async Task ExecuteProxyOperationAsync(this HttpContext context,
         }
 
         internal static ValueTask<string> GetEndpointFromComputerAsync(this HttpContext context, EndpointComputerToValueTask computer) =>
-            computer(context, (context.GetRouteData()?.Values as IDictionary<string, object>) ?? new Dictionary<string, object>());
+            computer(context, context.GetRouteData()?.Values);
 
         internal static EndpointComputerToValueTask GetRunProxyComputer(EndpointComputerToValueTask endpointComputer)
         {
diff --git a/src/Core/Helpers/Helpers.cs b/src/Core/Helpers/Helpers.cs
index 0bff089..64e35af 100644
--- a/src/Core/Helpers/Helpers.cs
+++ b/src/Core/Helpers/Helpers.cs
@@ -23,7 +23,7 @@ namespace AspNetCore.Proxy
     /// This takes the form `(<see cref="HttpContext"/>, <see cref="IDictionary{String, Object}"/>) => <see cref="ValueTask{String}"/>`.
     /// </summary>
     /// <param name="context">The HTTP context of the current request at runtime.</param>
-    /// <param name="arguments">The arguments of the current request at runtime.</param>
+    /// <param name="arguments">The arguments of the current request at runtime.  This may be `null`, if the route data is missing.</param>
     /// <returns>The endpoint string as a <see cref="ValueTask{String}"/>.</returns>
     public delegate ValueTask<string> EndpointComputerToValueTask(HttpContext context, IDictionary<string, object> arguments);