diff --git a/src/GeneratedEndpoints/MinimalApiGenerator.cs b/src/GeneratedEndpoints/MinimalApiGenerator.cs
index 6cd6336..7636570 100644
--- a/src/GeneratedEndpoints/MinimalApiGenerator.cs
+++ b/src/GeneratedEndpoints/MinimalApiGenerator.cs
@@ -58,6 +58,7 @@ public sealed class MinimalApiGenerator : IIncrementalGenerator
     private const string NameAttributeNamedParameter = "Name";
     private const string SummaryAttributeNamedParameter = "Summary";
     private const string DescriptionAttributeNamedParameter = "Description";
+    private const string ResponseTypeAttributeNamedParameter = "ResponseType";
 
     private const string RequireAuthorizationAttributeName = "RequireAuthorizationAttribute";
     private const string RequireAuthorizationAttributeFullyQualifiedName = $"{AttributesNamespace}.{RequireAuthorizationAttributeName}";
@@ -355,10 +356,10 @@ namespace {{AttributesNamespace}};
                                 [global::System.AttributeUsage(global::System.AttributeTargets.Class | global::System.AttributeTargets.Method, Inherited = false, AllowMultiple = true)]
                                 internal sealed class {{ProducesResponseAttributeName}} : global::System.Attribute
                                 {
-                                    /// <summary>
-                                    /// Gets the response type produced by the endpoint.
-                                    /// </summary>
-                                    public global::System.Type ResponseType { get; }
+                                /// <summary>
+                                /// Gets the response type produced by the endpoint.
+                                /// </summary>
+                                public global::System.Type ResponseType { get; init; } = default!;
 
                                     /// <summary>
                                     /// Gets the HTTP status code returned by the endpoint.
@@ -378,13 +379,11 @@ internal sealed class {{ProducesResponseAttributeName}} : global::System.Attribu
                                     /// <summary>
                                     /// Initializes a new instance of the <see cref="{{ProducesResponseAttributeName}}"/> class.
                                     /// </summary>
-                                    /// <param name="responseType">The CLR type of the response body.</param>
                                     /// <param name="statusCode">The HTTP status code returned by the endpoint.</param>
                                     /// <param name="contentType">The primary content type produced by the endpoint.</param>
                                     /// <param name="additionalContentTypes">Additional content types produced by the endpoint.</param>
-                                    public {{ProducesResponseAttributeName}}(global::System.Type responseType, int statusCode = 200, string? contentType = null, params string[] additionalContentTypes)
+                                    public {{ProducesResponseAttributeName}}(int statusCode = 200, string? contentType = null, params string[] additionalContentTypes)
                                     {
-                                        ResponseType = responseType ?? throw new global::System.ArgumentNullException(nameof(responseType));
                                         StatusCode = statusCode;
                                         ContentType = contentType;
                                         AdditionalContentTypes = additionalContentTypes ?? [];
@@ -971,18 +970,17 @@ private static void TryAddProducesMetadata(
                 ? GetStringArrayValues(attribute.ConstructorArguments[2])
                 : null;
         }
-        else if (attribute.ConstructorArguments.Length >= 1 &&
-                 attribute.ConstructorArguments[0].Value is ITypeSymbol responseTypeSymbol)
+        else if (GetNamedTypeSymbol(attribute, ResponseTypeAttributeNamedParameter) is { } responseTypeSymbol)
         {
             responseType = responseTypeSymbol.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
-            statusCode = attribute.ConstructorArguments.Length > 1 && attribute.ConstructorArguments[1].Value is int producesStatusCode
+            statusCode = attribute.ConstructorArguments.Length > 0 && attribute.ConstructorArguments[0].Value is int producesStatusCode
                 ? producesStatusCode
                 : 200;
-            contentType = attribute.ConstructorArguments.Length > 2
-                ? NormalizeOptionalContentType(attribute.ConstructorArguments[2].Value as string)
+            contentType = attribute.ConstructorArguments.Length > 1
+                ? NormalizeOptionalContentType(attribute.ConstructorArguments[1].Value as string)
                 : null;
-            additionalContentTypes = attribute.ConstructorArguments.Length > 3
-                ? GetStringArrayValues(attribute.ConstructorArguments[3])
+            additionalContentTypes = attribute.ConstructorArguments.Length > 2
+                ? GetStringArrayValues(attribute.ConstructorArguments[2])
                 : null;
         }
         else
@@ -994,6 +992,17 @@ private static void TryAddProducesMetadata(
         producesList.Add(new ProducesMetadata(responseType, statusCode, contentType, additionalContentTypes));
     }
 
+    private static ITypeSymbol? GetNamedTypeSymbol(AttributeData attribute, string namedParameter)
+    {
+        foreach (var namedArg in attribute.NamedArguments)
+        {
+            if (namedArg.Key == namedParameter && namedArg.Value.Value is ITypeSymbol typeSymbol)
+                return typeSymbol;
+        }
+
+        return null;
+    }
+
     private static EquatableImmutableArray<string> MergeUnion(EquatableImmutableArray<string>? existing, IEnumerable<string> values)
     {
         var list = new List<string>();