Rename from "top" to "maxCount" in paging operations

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/src/Providers/RestClientProvider.cs

@@ -24,6 +24,8 @@ public class RestClientProvider : TypeProvider
         private const string RepeatabilityRequestIdHeader = "Repeatability-Request-ID";
         private const string RepeatabilityFirstSentHeader = "Repeatability-First-Sent";
         private const string MaxPageSizeParameterName = "maxpagesize";
+        private const string TopParameterName = "top";
+        private const string MaxCountParameterName = "maxCount";
         private const string ApiVersionParameterName = "api-version";
 
         private static readonly Dictionary<string, ParameterProvider> _knownSpecialHeaderParams = new(StringComparer.OrdinalIgnoreCase)
@@ -955,6 +957,13 @@ internal static List<ParameterProvider> GetMethodParameters(
                     continue;
                 }
 
+                // For paging operations, rename "top" parameter to "maxCount"
+                if (serviceMethod is InputPagingServiceMethod &&
+                    string.Equals(inputParam.Name, TopParameterName, StringComparison.OrdinalIgnoreCase))
+                {
+                    inputParam.Update(name: MaxCountParameterName);
+                }
+
                 ParameterProvider? parameter = ScmCodeModelGenerator.Instance.TypeFactory.CreateParameter(inputParam)?.ToPublicInputParameter();
                 if (parameter is null)
                 {

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/CollectionResultDefinitions/ListPageableTests.cs

@@ -40,6 +40,36 @@ public void NoNextLinkOrContinuationTokenAsync()
             Assert.AreEqual(Helpers.GetExpectedFromFile(), file.Content);
         }
 
+        [Test]
+        public void TopParameterRenamedToMaxCountInPagingOperation()
+        {
+            var topParameter = InputFactory.QueryParameter("top", InputPrimitiveType.Int32);
+            var pagingMetadata = InputFactory.PagingMetadata(["items"], null, null);
+            var responseModel = InputFactory.Model("Response", properties: [
+                InputFactory.Property("items", InputFactory.Array(InputPrimitiveType.String))
+            ]);
+            var response = InputFactory.OperationResponse([200], responseModel);
+            var operation = InputFactory.Operation("getItems", parameters: [topParameter], responses: [response]);
+            var pagingMethod = InputFactory.PagingServiceMethod("getItems", operation, pagingMetadata: pagingMetadata);
+            var client = InputFactory.Client("testClient", methods: [pagingMethod]);
+
+            MockHelpers.LoadMockGenerator(inputModels: () => [responseModel], clients: () => [client]);
+
+            var restClientProviders = ScmCodeModelGenerator.Instance.OutputLibrary.TypeProviders
+                .OfType<RestClientProvider>().ToList();
+
+            Assert.IsTrue(restClientProviders.Count > 0, "RestClientProvider should be generated");
+
+            var parameterNames = restClientProviders
+                .SelectMany(p => p.Methods)
+                .SelectMany(m => m.Signature.Parameters)
+                .Select(param => param.Name)
+                .ToList();
+
+            Assert.Contains("maxCount", parameterNames, "Should contain 'maxCount' parameter");
+            Assert.IsFalse(parameterNames.Contains("top"), "Should not contain 'top' parameter after renaming");
+        }
+
         [Test]
         public void NoNextLinkOrContinuationTokenOfT()
         {

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.Input/src/InputTypes/InputParameter.cs

@@ -31,9 +31,17 @@ protected InputParameter(
         /// Update the instance with given parameters.
         /// </summary>
         /// <param name="scope">The scope of the <see cref="InputParameter"/></param>
-        public void Update(InputParameterScope scope)
+        /// <param name="name">The name of the <see cref="InputParameter"/></param>
+        public void Update(InputParameterScope? scope = null, string? name = null)
         {
-            Scope = scope;
+            if (scope.HasValue)
+            {
+                Scope = scope.Value;
+            }
+            if (name != null)
+            {
+                Name = name;
+            }
         }
 
         public static InputParameterScope ParseScope(InputType type, string name, string? scope)