diff --git a/docs/features/service_client_constructors.md b/docs/features/service_client_constructors.md
new file mode 100644
index 00000000000..eec88608b82
--- /dev/null
+++ b/docs/features/service_client_constructors.md
@@ -0,0 +1,68 @@
+## Service Client Constrctors
+
+Scope: This document only applies to DPG libraries.
+
+There will be two **public** client constructors in a generated service client:
+
+**One primary public constructor with:**
+- An `endpoint` parameter (no matter it is required or optional).
+- All the **required** client parameters.
+- A `ClientOptions` parameter.
+
+**One secondary public constructor with:**
+- All the **required** client parameters (without the `ClientOptions` parameter and **optional** paramters).
+
+The secondary public constructor calls the primary public constructor underneath with default values of `endpoint` (if any) and `ClientOptions`.
+
+For example, required parameters `Uri endpoint` and `AzureKeyCredential credential` are defined, then the generated public constructors are:
+
+```C#
+public ServiceClient(Uri endpoint, AzureKeyCredential credential) : this(endpoint, credential, new ServiceClientOptions()) {}
+
+public ServiceClient(Uri endpoint, AzureKeyCredential credential, ServiceClientOptions options) {}
+```
+
+Usually, all the client parameters are required. But if some additional optional client parameters are defined, all the optional client parameters will go to `ClientOptions`, except for the `endpoint` parameter.
+
+For example, if an optional parameter `string optional` is defined, the `ClientOptions` will have a new property as
+
+```C#
+public partial class ServiceClientOptions : ClientOptions
+{
+    /* Other irrelevant lines*/
+
+    public string Optional { get; set; }
+}
+```
+
+The signature of the public constructors will not change, but its implementation will change to
+```C#
+public ServiceClient(Uri endpoint, AzureKeyCredential credential) : this(endpoint, credential, new ServiceClientOptions()) {}
+
+public ServiceClient(Uri endpoint, AzureKeyCredential credential, ServiceClientOptions options)
+{
+    /* Other irrelevant lines*/
+
+    _optional = options.Optional;
+}
+```
+
+If the optional client parameters contain `endpoint`, it will still be in the client constructor, not going to `ClientOptions`. For example, if an optional parameter `string optional` is defined, an optional `endpoint` with default value `"http://localhost:3000"`, and a required parameter `AzureKeyCredential credential`, the generated public constructors are:
+
+```C#
+public ServiceClient(AzureKeyCredential credential) : this(new Uri("http://localhost:3000"), credential, new ServiceClientOptions()) {}
+
+public ServiceClient(Uri endpoint, AzureKeyCredential credential, ServiceClientOptions options)
+{
+    /* Other irrelevant lines*/
+
+    _optional = options.Optional;
+}
+
+public partial class ServiceClientOptions : ClientOptions
+{
+    /* Other irrelevant lines*/
+
+    public string Optional { get; set; }
+}
+```
\ No newline at end of file
diff --git a/src/AutoRest.CSharp/Common/Generation/Writers/ClientOptionsWriter.cs b/src/AutoRest.CSharp/Common/Generation/Writers/ClientOptionsWriter.cs
index e3acfa49c58..68554aafc6c 100644
--- a/src/AutoRest.CSharp/Common/Generation/Writers/ClientOptionsWriter.cs
+++ b/src/AutoRest.CSharp/Common/Generation/Writers/ClientOptionsWriter.cs
@@ -5,6 +5,7 @@
 using System.Linq;
 using AutoRest.CSharp.Common.Input;
 using AutoRest.CSharp.Output.Models.Types;
+using AutoRest.CSharp.Utilities;
 
 namespace AutoRest.CSharp.Generation.Writers
 {
@@ -49,6 +50,15 @@ public static void WriteClientOptions(CodeWriter writer, ClientOptionsTypeProvid
                                 writer.Line($"_ => throw new {typeof(NotSupportedException)}()");
                             }
                         }
+
+                        writer.Line();
+                    }
+
+                    foreach (var parameter in clientOptions.AdditionalParameters)
+                    {
+                        writer.WriteXmlDocumentationSummary(parameter.Description);
+                        writer.Line($"public {parameter.Type} {parameter.Name.ToCleanName()} {{ get; set; }}");
+                        writer.Line();
                     }
                 }
             }
diff --git a/src/AutoRest.CSharp/Common/Input/CodeModelConverter.cs b/src/AutoRest.CSharp/Common/Input/CodeModelConverter.cs
index ac759a8c00f..5f9f060814f 100644
--- a/src/AutoRest.CSharp/Common/Input/CodeModelConverter.cs
+++ b/src/AutoRest.CSharp/Common/Input/CodeModelConverter.cs
@@ -452,6 +452,11 @@ private static InputLiteralType CreateLiteralType(ConstantSchema constantSchema,
         {
             if (parameter.ClientDefaultValue != null)
             {
+                if (parameter.Origin == "modelerfour:synthesized/host" && (string)parameter.ClientDefaultValue == "")
+                {
+                    return null;
+                }
+
                 return new InputConstant(Value: parameter.ClientDefaultValue, Type: CreateType(parameter.Schema, _modelsCache, parameter.IsNullable));
             }
 
diff --git a/src/AutoRest.CSharp/Common/Output/Models/Shared/KnownParameters.cs b/src/AutoRest.CSharp/Common/Output/Models/Shared/KnownParameters.cs
index 7ea3d0be133..a0835550df0 100644
--- a/src/AutoRest.CSharp/Common/Output/Models/Shared/KnownParameters.cs
+++ b/src/AutoRest.CSharp/Common/Output/Models/Shared/KnownParameters.cs
@@ -26,7 +26,7 @@ internal static class KnownParameters
         public static readonly Parameter Pipeline = new("pipeline", $"The HTTP pipeline for sending and receiving REST requests and responses", new CSharpType(Configuration.ApiTypes.HttpPipelineType), null, ValidationType.AssertNotNull, null);
         public static readonly Parameter KeyAuth = new("keyCredential", $"The key credential to copy", new CSharpType(Configuration.ApiTypes.KeyCredentialType), null, ValidationType.None, null);
         public static readonly Parameter TokenAuth = new("tokenCredential", $"The token credential to copy", new CSharpType(typeof(TokenCredential)), null, ValidationType.None, null);
-        public static readonly Parameter Endpoint = new("endpoint", $"Service endpoint", new CSharpType(typeof(Uri)), null, ValidationType.None, null, RequestLocation: RequestLocation.Uri);
+        public static readonly Parameter Endpoint = new("endpoint", $"Service endpoint", new CSharpType(typeof(Uri)), null, ValidationType.None, null, RequestLocation: RequestLocation.Uri, IsEndpoint: true);
 
         public static readonly Parameter PageSizeHint = new("pageSizeHint", $"The number of items per {typeof(Page<>):C} that should be requested (from service operations that support it). It's not guaranteed that the value will be respected.", new CSharpType(typeof(int), true), null, ValidationType.None, null);
         public static readonly Parameter NextLink = new("nextLink", $"Continuation token", typeof(string), null, ValidationType.None, null);
diff --git a/src/AutoRest.CSharp/Common/Output/Models/Shared/Parameter.cs b/src/AutoRest.CSharp/Common/Output/Models/Shared/Parameter.cs
index 1c0373fcd18..23f5524e80d 100644
--- a/src/AutoRest.CSharp/Common/Output/Models/Shared/Parameter.cs
+++ b/src/AutoRest.CSharp/Common/Output/Models/Shared/Parameter.cs
@@ -16,7 +16,7 @@
 
 namespace AutoRest.CSharp.Output.Models.Shared
 {
-    internal record Parameter(string Name, FormattableString? Description, CSharpType Type, Constant? DefaultValue, ValidationType Validation, FormattableString? Initializer, bool IsApiVersionParameter = false, bool IsResourceIdentifier = false, bool SkipUrlEncoding = false, RequestLocation RequestLocation = RequestLocation.None, SerializationFormat SerializationFormat = SerializationFormat.Default, bool IsPropertyBag = false)
+    internal record Parameter(string Name, FormattableString? Description, CSharpType Type, Constant? DefaultValue, ValidationType Validation, FormattableString? Initializer, bool IsApiVersionParameter = false, bool IsEndpoint = false, bool IsResourceIdentifier = false, bool SkipUrlEncoding = false, RequestLocation RequestLocation = RequestLocation.None, SerializationFormat SerializationFormat = SerializationFormat.Default, bool IsPropertyBag = false)
     {
         public CSharpAttribute[] Attributes { get; init; } = Array.Empty<CSharpAttribute>();
         public bool IsOptionalInSignature => DefaultValue != null;
@@ -74,6 +74,7 @@ public static Parameter FromInputParameter(in InputParameter operationParameter,
                 validation,
                 initializer,
                 IsApiVersionParameter: operationParameter.IsApiVersion,
+                IsEndpoint: operationParameter.IsEndpoint,
                 IsResourceIdentifier: operationParameter.IsResourceParameter,
                 SkipUrlEncoding: skipUrlEncoding,
                 RequestLocation: requestLocation,
@@ -167,6 +168,7 @@ public static Parameter FromRequestParameter(in RequestParameter requestParamete
                 validation,
                 initializer,
                 IsApiVersionParameter: requestParameter.Origin == "modelerfour:synthesized/api-version",
+                IsEndpoint: IsEndpointParameter(requestParameter),
                 IsResourceIdentifier: requestParameter.IsResourceParameter,
                 SkipUrlEncoding: skipUrlEncoding,
                 RequestLocation: requestLocation);
diff --git a/src/AutoRest.CSharp/Common/Output/Models/Types/ClientOptionsTypeProvider.cs b/src/AutoRest.CSharp/Common/Output/Models/Types/ClientOptionsTypeProvider.cs
index f75a1f599a3..384b0afccfb 100644
--- a/src/AutoRest.CSharp/Common/Output/Models/Types/ClientOptionsTypeProvider.cs
+++ b/src/AutoRest.CSharp/Common/Output/Models/Types/ClientOptionsTypeProvider.cs
@@ -7,6 +7,7 @@
 using System.Linq;
 using System.Text;
 using AutoRest.CSharp.Input.Source;
+using AutoRest.CSharp.Output.Models.Shared;
 
 namespace AutoRest.CSharp.Output.Models.Types
 {
@@ -16,6 +17,7 @@ internal sealed class ClientOptionsTypeProvider : TypeProvider
 
         public FormattableString Description { get; }
         public IReadOnlyList<ApiVersion>? ApiVersions { get; }
+        public IReadOnlyList<Parameter> AdditionalParameters { get; init; }
         protected override string DefaultName { get; }
         protected override string DefaultAccessibility { get; }
 
@@ -27,6 +29,8 @@ public ClientOptionsTypeProvider(IReadOnlyList<string>? versions, string name, s
 
             if (versions is not null)
                 ApiVersions = ConvertApiVersions(versions);
+
+            AdditionalParameters = Array.Empty<Parameter>();
         }
 
         private static ApiVersion[] ConvertApiVersions(IReadOnlyList<string> versions) =>
diff --git a/src/AutoRest.CSharp/LowLevel/Generation/DpgClientWriter.cs b/src/AutoRest.CSharp/LowLevel/Generation/DpgClientWriter.cs
index 7796fd1042c..34c1d91aa88 100644
--- a/src/AutoRest.CSharp/LowLevel/Generation/DpgClientWriter.cs
+++ b/src/AutoRest.CSharp/LowLevel/Generation/DpgClientWriter.cs
@@ -259,6 +259,10 @@ private void WritePrimaryPublicConstructor(ConstructorSignature signature)
                         {
                             _writer.Line($"{field.Name:I} = {clientOptionsParameter.Name:I}.Version;");
                         }
+                        else if (_client.ClientOptions.AdditionalParameters.Contains(parameter))
+                        {
+                            _writer.Line($"{field.Name:I} = {clientOptionsParameter.Name:I}.{parameter.Name.ToCleanName()};");
+                        }
                         else
                         {
                             _writer.Line($"{field.Name:I} = {parameter.Name:I};");
diff --git a/src/AutoRest.CSharp/LowLevel/Output/DpgOutputLibraryBuilder.cs b/src/AutoRest.CSharp/LowLevel/Output/DpgOutputLibraryBuilder.cs
index 3408e712da8..54408c80912 100644
--- a/src/AutoRest.CSharp/LowLevel/Output/DpgOutputLibraryBuilder.cs
+++ b/src/AutoRest.CSharp/LowLevel/Output/DpgOutputLibraryBuilder.cs
@@ -11,6 +11,7 @@
 using AutoRest.CSharp.Generation.Types;
 using AutoRest.CSharp.Input.Source;
 using AutoRest.CSharp.Output.Builders;
+using AutoRest.CSharp.Output.Models.Shared;
 using AutoRest.CSharp.Output.Models.Types;
 using AutoRest.CSharp.Utilities;
 using Microsoft.CodeAnalysis;
@@ -44,7 +45,8 @@ public DpgOutputLibrary Build(bool isTspInput)
                 .ToDictionary(ci => ci.Name);
             AssignParentClients(inputClients, clientInfosByName);
             var topLevelClientInfos = SetHierarchy(clientInfosByName);
-            var clientOptions = CreateClientOptions(topLevelClientInfos);
+            var parametersInClientOptions = new List<Parameter>();
+            var clientOptions = CreateClientOptions(topLevelClientInfos, parametersInClientOptions);
 
             SetRequestsToClients(clientInfosByName.Values);
 
@@ -59,7 +61,7 @@ public DpgOutputLibrary Build(bool isTspInput)
                 CreateModels(models, library.TypeFactory);
                 CreateEnums(enums, models, library.TypeFactory);
             }
-            CreateClients(clients, topLevelClientInfos, library.TypeFactory, clientOptions);
+            CreateClients(clients, topLevelClientInfos, library.TypeFactory, clientOptions, parametersInClientOptions);
 
             return library;
         }
@@ -459,7 +461,7 @@ private static IReadOnlyList<InputParameter> UpdateOperationParameters(IReadOnly
             return parameters;
         }
 
-        private ClientOptionsTypeProvider CreateClientOptions(IReadOnlyList<ClientInfo> topLevelClientInfos)
+        private ClientOptionsTypeProvider CreateClientOptions(IReadOnlyList<ClientInfo> topLevelClientInfos, List<Parameter> parametersInClientOptions)
         {
             var clientName = topLevelClientInfos.Count == 1
                 ? topLevelClientInfos[0].Name
@@ -477,7 +479,10 @@ private ClientOptionsTypeProvider CreateClientOptions(IReadOnlyList<ClientInfo>
                     throw new InvalidOperationException("Multiple API versions are not supported in the unbranded path.");
                 apiVersions = null;
             }
-            return new ClientOptionsTypeProvider(apiVersions, clientOptionsName, _defaultNamespace, description, _sourceInputModel);
+            return new ClientOptionsTypeProvider(apiVersions, clientOptionsName, _defaultNamespace, description, _sourceInputModel)
+            {
+                AdditionalParameters = parametersInClientOptions
+            };
         }
 
         private static ClientInfo CreateClientInfo(InputClient ns, SourceInputModel? sourceInputModel, string rootNamespaceName)
@@ -626,9 +631,9 @@ private static void SetRequestToClient(ClientInfo clientInfo, InputOperation ope
             clientInfo.Requests.Add(operation);
         }
 
-        private void CreateClients(List<LowLevelClient> allClients, IEnumerable<ClientInfo> topLevelClientInfos, TypeFactory typeFactory, ClientOptionsTypeProvider clientOptions)
+        private void CreateClients(List<LowLevelClient> allClients, IEnumerable<ClientInfo> topLevelClientInfos, TypeFactory typeFactory, ClientOptionsTypeProvider clientOptions, List<Parameter> parametersInClientOptions)
         {
-            var topLevelClients = CreateClients(topLevelClientInfos, typeFactory, clientOptions, null);
+            var topLevelClients = CreateClients(topLevelClientInfos, typeFactory, clientOptions, null, parametersInClientOptions);
 
             // Simple implementation of breadth first traversal
             allClients.AddRange(topLevelClients);
@@ -638,7 +643,7 @@ private void CreateClients(List<LowLevelClient> allClients, IEnumerable<ClientIn
             }
         }
 
-        private IEnumerable<LowLevelClient> CreateClients(IEnumerable<ClientInfo> clientInfos, TypeFactory typeFactory, ClientOptionsTypeProvider clientOptions, LowLevelClient? parentClient)
+        private IEnumerable<LowLevelClient> CreateClients(IEnumerable<ClientInfo> clientInfos, TypeFactory typeFactory, ClientOptionsTypeProvider clientOptions, LowLevelClient? parentClient, List<Parameter> parametersInClientOptions)
         {
             foreach (var clientInfo in clientInfos)
             {
@@ -673,7 +678,9 @@ private IEnumerable<LowLevelClient> CreateClients(IEnumerable<ClientInfo> client
                     SubClients = subClients
                 };
 
-                subClients.AddRange(CreateClients(clientInfo.Children, typeFactory, clientOptions, client));
+                subClients.AddRange(CreateClients(clientInfo.Children, typeFactory, clientOptions, client, parametersInClientOptions));
+                // parametersInClientOptions is assigned to ClientOptionsTypeProvider.AdditionalProperties before, which makes sure AdditionalProperties is readonly and won't change after ClientOptionsTypeProvider is built.
+                parametersInClientOptions.AddRange(client.GetOptionalParametersInOptions());
 
                 yield return client;
             }
diff --git a/src/AutoRest.CSharp/LowLevel/Output/LowLevelClient.cs b/src/AutoRest.CSharp/LowLevel/Output/LowLevelClient.cs
index 10a6249d4f1..1c6f9921570 100644
--- a/src/AutoRest.CSharp/LowLevel/Output/LowLevelClient.cs
+++ b/src/AutoRest.CSharp/LowLevel/Output/LowLevelClient.cs
@@ -140,7 +140,7 @@ public static IEnumerable<LowLevelClientMethod> BuildMethods(LowLevelClient? cli
             if (!IsSubClient)
             {
                 var requiredParameters = RestClientBuilder.GetRequiredParameters(orderedParameters).ToArray();
-                var optionalParameters = RestClientBuilder.GetOptionalParameters(orderedParameters).Append(CreateOptionsParameter()).ToArray();
+                var optionalParameters = GetOptionalParametersInConstructor(RestClientBuilder.GetOptionalParameters(orderedParameters).Append(CreateOptionsParameter())).ToArray();
 
                 return (
                     BuildPrimaryConstructors(requiredParameters, optionalParameters).ToArray(),
@@ -153,6 +153,17 @@ public static IEnumerable<LowLevelClientMethod> BuildMethods(LowLevelClient? cli
             }
         }
 
+        private IEnumerable<Parameter> GetOptionalParametersInConstructor(IEnumerable<Parameter> optionalParameters)
+        {
+            return optionalParameters.Where(
+                p => ClientOptions.Type.EqualsIgnoreNullable(p.Type) || p.IsEndpoint); // Endpoint is an exception, even it is optional, still need to be the parameter of constructor
+        }
+
+        public IEnumerable<Parameter> GetOptionalParametersInOptions()
+        {
+            return RestClientBuilder.GetOptionalParameters(Parameters).Where(p => !p.IsEndpoint);
+        }
+
         private IEnumerable<ConstructorSignature> BuildPrimaryConstructors(IReadOnlyList<Parameter> requiredParameters, IReadOnlyList<Parameter> optionalParameters)
         {
             var optionalToRequired = optionalParameters
diff --git a/test/AutoRest.TestServerLowLevel.Tests/url-path-items.cs b/test/AutoRest.TestServerLowLevel.Tests/url-path-items.cs
index 386833e238e..3f351aef763 100644
--- a/test/AutoRest.TestServerLowLevel.Tests/url-path-items.cs
+++ b/test/AutoRest.TestServerLowLevel.Tests/url-path-items.cs
@@ -12,55 +12,76 @@ public class UrlPathItemsTests : TestServerLowLevelTestBase
     {
         [Test]
         public Task UrlPathItemGetAll() => TestStatus(async (host) =>
-            await new PathItemsClient(globalStringPath: "globalStringPath",
-                    globalStringQuery: "globalStringQuery",
+        {
+            var options = new AutoRestUrlTestServiceClientOptions()
+            {
+                GlobalStringQuery = "globalStringQuery"
+            };
+            return await new PathItemsClient(globalStringPath: "globalStringPath",
                     credential: Key,
                     endpoint: host,
-                    options: null)
+                    options: options)
                 .GetAllWithValuesAsync(
                     pathItemStringPath: "pathItemStringPath",
                     pathItemStringQuery: "pathItemStringQuery",
                     localStringPath: "localStringPath",
-                    localStringQuery: "localStringQuery"));
+                    localStringQuery: "localStringQuery");
+        });
 
         [Test]
         public Task UrlPathItemGetPathItemAndLocalNull() => TestStatus(async (host) =>
-            await new PathItemsClient(globalStringPath: "globalStringPath",
-                    globalStringQuery: "globalStringQuery",
+        {
+            var options = new AutoRestUrlTestServiceClientOptions()
+            {
+                GlobalStringQuery = "globalStringQuery"
+            };
+            return await new PathItemsClient(globalStringPath: "globalStringPath",
                     credential: Key,
                     endpoint: host,
-                    options: null)
+                    options: options)
                 .GetLocalPathItemQueryNullAsync(
                     pathItemStringPath: "pathItemStringPath",
                     pathItemStringQuery: null,
                     localStringPath: "localStringPath",
-                    localStringQuery: null));
+                    localStringQuery: null);
+        });
+
 
         [Test]
         public Task UrlPathItemGetGlobalNull() => TestStatus(async (host) =>
-            await new PathItemsClient(globalStringPath: "globalStringPath",
-                    endpoint: host,
-                    credential: Key,
-                    globalStringQuery: null,
-                    options: null)
-                .GetGlobalQueryNullAsync(
-                    pathItemStringPath: "pathItemStringPath",
-                    pathItemStringQuery: "pathItemStringQuery",
-                    localStringPath: "localStringPath",
-                    localStringQuery: "localStringQuery"));
+        {
+            var options = new AutoRestUrlTestServiceClientOptions()
+            {
+                GlobalStringQuery = null
+            };
+            return await new PathItemsClient(globalStringPath: "globalStringPath",
+                        endpoint: host,
+                        credential: Key,
+                        options: options)
+                    .GetGlobalQueryNullAsync(
+                        pathItemStringPath: "pathItemStringPath",
+                        pathItemStringQuery: "pathItemStringQuery",
+                        localStringPath: "localStringPath",
+                        localStringQuery: "localStringQuery");
+        });
 
         [Test]
         public Task UrlPathItemGetGlobalAndLocalNull() => TestStatus(async (host) =>
-            await new PathItemsClient(
-                    globalStringPath: "globalStringPath",
-                    endpoint: host,
-                    credential: Key,
-                    globalStringQuery: null,
-                    options: null)
-                .GetGlobalAndLocalQueryNullAsync(
-                pathItemStringPath: "pathItemStringPath",
-                pathItemStringQuery: "pathItemStringQuery",
-                localStringPath: "localStringPath",
-                localStringQuery: null));
+        {
+            var options = new AutoRestUrlTestServiceClientOptions()
+            {
+                GlobalStringQuery = null
+            };
+            return await new PathItemsClient(
+                        globalStringPath: "globalStringPath",
+                        endpoint: host,
+                        credential: Key,
+                        options: options)
+                    .GetGlobalAndLocalQueryNullAsync(
+                    pathItemStringPath: "pathItemStringPath",
+                    pathItemStringQuery: "pathItemStringQuery",
+                    localStringPath: "localStringPath",
+                    localStringQuery: null);
+        });
     }
 }
diff --git a/test/TestProjects/ApiVersion/Generated/ApiVersionClient.cs b/test/TestProjects/ApiVersion/Generated/ApiVersionClient.cs
index a868168e8c8..f28e010cec7 100644
--- a/test/TestProjects/ApiVersion/Generated/ApiVersionClient.cs
+++ b/test/TestProjects/ApiVersion/Generated/ApiVersionClient.cs
@@ -31,8 +31,8 @@ protected ApiVersionClient()
         /// <param name="pipeline"> The HTTP pipeline for sending and receiving REST requests and responses. </param>
         /// <param name="endpoint"> server parameter. </param>
         /// <param name="apiVersion"> Api Version. </param>
-        /// <exception cref="ArgumentNullException"> <paramref name="clientDiagnostics"/>, <paramref name="pipeline"/> or <paramref name="apiVersion"/> is null. </exception>
-        internal ApiVersionClient(ClientDiagnostics clientDiagnostics, HttpPipeline pipeline, Uri endpoint = null, string apiVersion = "1.0.0")
+        /// <exception cref="ArgumentNullException"> <paramref name="clientDiagnostics"/>, <paramref name="pipeline"/>, <paramref name="endpoint"/> or <paramref name="apiVersion"/> is null. </exception>
+        internal ApiVersionClient(ClientDiagnostics clientDiagnostics, HttpPipeline pipeline, Uri endpoint, string apiVersion = "1.0.0")
         {
             RestClient = new ApiVersionRestClient(clientDiagnostics, pipeline, endpoint, apiVersion);
             _clientDiagnostics = clientDiagnostics;
diff --git a/test/TestProjects/ApiVersion/Generated/ApiVersionRestClient.cs b/test/TestProjects/ApiVersion/Generated/ApiVersionRestClient.cs
index 9a4fb271dc2..6182cf91813 100644
--- a/test/TestProjects/ApiVersion/Generated/ApiVersionRestClient.cs
+++ b/test/TestProjects/ApiVersion/Generated/ApiVersionRestClient.cs
@@ -29,12 +29,12 @@ internal partial class ApiVersionRestClient
         /// <param name="pipeline"> The HTTP pipeline for sending and receiving REST requests and responses. </param>
         /// <param name="endpoint"> server parameter. </param>
         /// <param name="apiVersion"> Api Version. </param>
-        /// <exception cref="ArgumentNullException"> <paramref name="clientDiagnostics"/>, <paramref name="pipeline"/> or <paramref name="apiVersion"/> is null. </exception>
-        public ApiVersionRestClient(ClientDiagnostics clientDiagnostics, HttpPipeline pipeline, Uri endpoint = null, string apiVersion = "1.0.0")
+        /// <exception cref="ArgumentNullException"> <paramref name="clientDiagnostics"/>, <paramref name="pipeline"/>, <paramref name="endpoint"/> or <paramref name="apiVersion"/> is null. </exception>
+        public ApiVersionRestClient(ClientDiagnostics clientDiagnostics, HttpPipeline pipeline, Uri endpoint, string apiVersion = "1.0.0")
         {
             ClientDiagnostics = clientDiagnostics ?? throw new ArgumentNullException(nameof(clientDiagnostics));
             _pipeline = pipeline ?? throw new ArgumentNullException(nameof(pipeline));
-            _endpoint = endpoint ?? new Uri("");
+            _endpoint = endpoint ?? throw new ArgumentNullException(nameof(endpoint));
             _apiVersion = apiVersion ?? throw new ArgumentNullException(nameof(apiVersion));
         }
 
diff --git a/test/TestProjects/ModelWithConverterUsage/Generated/ModelWithConverterUsageClient.cs b/test/TestProjects/ModelWithConverterUsage/Generated/ModelWithConverterUsageClient.cs
index 824bb9030d5..6f558ec5521 100644
--- a/test/TestProjects/ModelWithConverterUsage/Generated/ModelWithConverterUsageClient.cs
+++ b/test/TestProjects/ModelWithConverterUsage/Generated/ModelWithConverterUsageClient.cs
@@ -30,8 +30,8 @@ protected ModelWithConverterUsageClient()
         /// <param name="clientDiagnostics"> The handler for diagnostic messaging in the client. </param>
         /// <param name="pipeline"> The HTTP pipeline for sending and receiving REST requests and responses. </param>
         /// <param name="endpoint"> server parameter. </param>
-        /// <exception cref="ArgumentNullException"> <paramref name="clientDiagnostics"/> or <paramref name="pipeline"/> is null. </exception>
-        internal ModelWithConverterUsageClient(ClientDiagnostics clientDiagnostics, HttpPipeline pipeline, Uri endpoint = null)
+        /// <exception cref="ArgumentNullException"> <paramref name="clientDiagnostics"/>, <paramref name="pipeline"/> or <paramref name="endpoint"/> is null. </exception>
+        internal ModelWithConverterUsageClient(ClientDiagnostics clientDiagnostics, HttpPipeline pipeline, Uri endpoint)
         {
             RestClient = new ModelWithConverterUsageRestClient(clientDiagnostics, pipeline, endpoint);
             _clientDiagnostics = clientDiagnostics;
diff --git a/test/TestProjects/ModelWithConverterUsage/Generated/ModelWithConverterUsageRestClient.cs b/test/TestProjects/ModelWithConverterUsage/Generated/ModelWithConverterUsageRestClient.cs
index b4efb5ab5cf..921beb077fa 100644
--- a/test/TestProjects/ModelWithConverterUsage/Generated/ModelWithConverterUsageRestClient.cs
+++ b/test/TestProjects/ModelWithConverterUsage/Generated/ModelWithConverterUsageRestClient.cs
@@ -28,12 +28,12 @@ internal partial class ModelWithConverterUsageRestClient
         /// <param name="clientDiagnostics"> The handler for diagnostic messaging in the client. </param>
         /// <param name="pipeline"> The HTTP pipeline for sending and receiving REST requests and responses. </param>
         /// <param name="endpoint"> server parameter. </param>
-        /// <exception cref="ArgumentNullException"> <paramref name="clientDiagnostics"/> or <paramref name="pipeline"/> is null. </exception>
-        public ModelWithConverterUsageRestClient(ClientDiagnostics clientDiagnostics, HttpPipeline pipeline, Uri endpoint = null)
+        /// <exception cref="ArgumentNullException"> <paramref name="clientDiagnostics"/>, <paramref name="pipeline"/> or <paramref name="endpoint"/> is null. </exception>
+        public ModelWithConverterUsageRestClient(ClientDiagnostics clientDiagnostics, HttpPipeline pipeline, Uri endpoint)
         {
             ClientDiagnostics = clientDiagnostics ?? throw new ArgumentNullException(nameof(clientDiagnostics));
             _pipeline = pipeline ?? throw new ArgumentNullException(nameof(pipeline));
-            _endpoint = endpoint ?? new Uri("");
+            _endpoint = endpoint ?? throw new ArgumentNullException(nameof(endpoint));
         }
 
         internal HttpMessage CreateOperationModelRequest(ModelClass value)
diff --git a/test/TestProjects/Parameters-LowLevel/src/Generated/ParametersLowlevelClientBuilderExtensions.cs b/test/TestProjects/Parameters-LowLevel/src/Generated/ParametersLowlevelClientBuilderExtensions.cs
deleted file mode 100644
index abea8b1d794..00000000000
--- a/test/TestProjects/Parameters-LowLevel/src/Generated/ParametersLowlevelClientBuilderExtensions.cs
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT License.
-
-// <auto-generated/>
-
-#nullable disable
-
-using System;
-using Azure;
-using Azure.Core.Extensions;
-using Parameters_LowLevel;
-
-namespace Microsoft.Extensions.Azure
-{
-    /// <summary> Extension methods to add <see cref="ParametersLowlevelClient"/> to client builder. </summary>
-    public static partial class ParametersLowLevelClientBuilderExtensions
-    {
-        /// <summary> Registers a <see cref="ParametersLowlevelClient"/> instance. </summary>
-        /// <param name="builder"> The builder to register with. </param>
-        /// <param name="endpoint"> server parameter. </param>
-        /// <param name="credential"> A credential used to authenticate to an Azure Service. </param>
-        public static IAzureClientBuilder<ParametersLowlevelClient, ParametersLowlevelClientOptions> AddParametersLowlevelClient<TBuilder>(this TBuilder builder, Uri endpoint, AzureKeyCredential credential)
-        where TBuilder : IAzureClientFactoryBuilder
-        {
-            return builder.RegisterClientFactory<ParametersLowlevelClient, ParametersLowlevelClientOptions>((options) => new ParametersLowlevelClient(endpoint, credential, options));
-        }
-
-        /// <summary> Registers a <see cref="ParametersLowlevelClient"/> instance. </summary>
-        /// <param name="builder"> The builder to register with. </param>
-        /// <param name="configuration"> The configuration values. </param>
-        public static IAzureClientBuilder<ParametersLowlevelClient, ParametersLowlevelClientOptions> AddParametersLowlevelClient<TBuilder, TConfiguration>(this TBuilder builder, TConfiguration configuration)
-        where TBuilder : IAzureClientFactoryBuilderWithConfiguration<TConfiguration>
-        {
-            return builder.RegisterClientFactory<ParametersLowlevelClient, ParametersLowlevelClientOptions>(configuration);
-        }
-    }
-}
diff --git a/test/TestProjects/ServiceVersionOverride-LowLevel/src/Generated/Docs/ServiceVersionOverrideClient.xml b/test/TestProjects/ServiceVersionOverride-LowLevel/src/Generated/Docs/ServiceVersionOverrideClient.xml
index 755ed41e6c9..1c6748e4e2e 100644
--- a/test/TestProjects/ServiceVersionOverride-LowLevel/src/Generated/Docs/ServiceVersionOverrideClient.xml
+++ b/test/TestProjects/ServiceVersionOverride-LowLevel/src/Generated/Docs/ServiceVersionOverrideClient.xml
@@ -5,7 +5,8 @@
       <example>
 This sample shows how to call OperationAsync.
 <code><![CDATA[
-ServiceVersionOverrideClient client = new ServiceVersionOverrideClient();
+Uri endpoint = new Uri("<https://my-service.azure.com>");
+ServiceVersionOverrideClient client = new ServiceVersionOverrideClient(endpoint);
 
 Response response = await client.OperationAsync("2.0");
 
@@ -13,7 +14,8 @@ Console.WriteLine(response.Status);
 ]]></code>
 This sample shows how to call OperationAsync with all parameters.
 <code><![CDATA[
-ServiceVersionOverrideClient client = new ServiceVersionOverrideClient();
+Uri endpoint = new Uri("<https://my-service.azure.com>");
+ServiceVersionOverrideClient client = new ServiceVersionOverrideClient(endpoint);
 
 Response response = await client.OperationAsync("2.0");
 
@@ -24,7 +26,8 @@ Console.WriteLine(response.Status);
       <example>
 This sample shows how to call Operation.
 <code><![CDATA[
-ServiceVersionOverrideClient client = new ServiceVersionOverrideClient();
+Uri endpoint = new Uri("<https://my-service.azure.com>");
+ServiceVersionOverrideClient client = new ServiceVersionOverrideClient(endpoint);
 
 Response response = client.Operation("2.0");
 
@@ -32,7 +35,8 @@ Console.WriteLine(response.Status);
 ]]></code>
 This sample shows how to call Operation with all parameters.
 <code><![CDATA[
-ServiceVersionOverrideClient client = new ServiceVersionOverrideClient();
+Uri endpoint = new Uri("<https://my-service.azure.com>");
+ServiceVersionOverrideClient client = new ServiceVersionOverrideClient(endpoint);
 
 Response response = client.Operation("2.0");
 
diff --git a/test/TestProjects/ServiceVersionOverride-LowLevel/src/Generated/ServiceVersionOverrideClient.cs b/test/TestProjects/ServiceVersionOverride-LowLevel/src/Generated/ServiceVersionOverrideClient.cs
index 278348087c8..0fc923b24d0 100644
--- a/test/TestProjects/ServiceVersionOverride-LowLevel/src/Generated/ServiceVersionOverrideClient.cs
+++ b/test/TestProjects/ServiceVersionOverride-LowLevel/src/Generated/ServiceVersionOverrideClient.cs
@@ -27,8 +27,15 @@ public partial class ServiceVersionOverrideClient
         /// <summary> The HTTP pipeline for sending and receiving REST requests and responses. </summary>
         public virtual HttpPipeline Pipeline => _pipeline;
 
+        /// <summary> Initializes a new instance of ServiceVersionOverrideClient for mocking. </summary>
+        protected ServiceVersionOverrideClient()
+        {
+        }
+
         /// <summary> Initializes a new instance of ServiceVersionOverrideClient. </summary>
-        public ServiceVersionOverrideClient() : this(new Uri(""), new ServiceVersionOverrideClientOptions())
+        /// <param name="endpoint"> server parameter. </param>
+        /// <exception cref="ArgumentNullException"> <paramref name="endpoint"/> is null. </exception>
+        public ServiceVersionOverrideClient(Uri endpoint) : this(endpoint, new ServiceVersionOverrideClientOptions())
         {
         }
 
diff --git a/test/TestProjects/ServiceVersionOverride-LowLevel/tests/Generated/Samples/Samples_ServiceVersionOverrideClient.cs b/test/TestProjects/ServiceVersionOverride-LowLevel/tests/Generated/Samples/Samples_ServiceVersionOverrideClient.cs
index 58014d6548b..8ba0d09edcc 100644
--- a/test/TestProjects/ServiceVersionOverride-LowLevel/tests/Generated/Samples/Samples_ServiceVersionOverrideClient.cs
+++ b/test/TestProjects/ServiceVersionOverride-LowLevel/tests/Generated/Samples/Samples_ServiceVersionOverrideClient.cs
@@ -20,7 +20,8 @@ public partial class Samples_ServiceVersionOverrideClient
         [Ignore("Only validating compilation of examples")]
         public void Example_Operation_ShortVersion()
         {
-            ServiceVersionOverrideClient client = new ServiceVersionOverrideClient();
+            Uri endpoint = new Uri("<https://my-service.azure.com>");
+            ServiceVersionOverrideClient client = new ServiceVersionOverrideClient(endpoint);
 
             Response response = client.Operation("2.0");
 
@@ -31,7 +32,8 @@ public void Example_Operation_ShortVersion()
         [Ignore("Only validating compilation of examples")]
         public async Task Example_Operation_ShortVersion_Async()
         {
-            ServiceVersionOverrideClient client = new ServiceVersionOverrideClient();
+            Uri endpoint = new Uri("<https://my-service.azure.com>");
+            ServiceVersionOverrideClient client = new ServiceVersionOverrideClient(endpoint);
 
             Response response = await client.OperationAsync("2.0");
 
@@ -42,7 +44,8 @@ public async Task Example_Operation_ShortVersion_Async()
         [Ignore("Only validating compilation of examples")]
         public void Example_Operation_AllParameters()
         {
-            ServiceVersionOverrideClient client = new ServiceVersionOverrideClient();
+            Uri endpoint = new Uri("<https://my-service.azure.com>");
+            ServiceVersionOverrideClient client = new ServiceVersionOverrideClient(endpoint);
 
             Response response = client.Operation("2.0");
 
@@ -53,7 +56,8 @@ public void Example_Operation_AllParameters()
         [Ignore("Only validating compilation of examples")]
         public async Task Example_Operation_AllParameters_Async()
         {
-            ServiceVersionOverrideClient client = new ServiceVersionOverrideClient();
+            Uri endpoint = new Uri("<https://my-service.azure.com>");
+            ServiceVersionOverrideClient client = new ServiceVersionOverrideClient(endpoint);
 
             Response response = await client.OperationAsync("2.0");
 
diff --git a/test/TestServerProjectsLowLevel/url/src/Generated/AutoRestUrlTestServiceClientOptions.cs b/test/TestServerProjectsLowLevel/url/src/Generated/AutoRestUrlTestServiceClientOptions.cs
index 26ab885d6bb..435af050aae 100644
--- a/test/TestServerProjectsLowLevel/url/src/Generated/AutoRestUrlTestServiceClientOptions.cs
+++ b/test/TestServerProjectsLowLevel/url/src/Generated/AutoRestUrlTestServiceClientOptions.cs
@@ -33,5 +33,8 @@ public AutoRestUrlTestServiceClientOptions(ServiceVersion version = LatestVersio
                 _ => throw new NotSupportedException()
             };
         }
+
+        /// <summary> should contain value null. </summary>
+        public string GlobalStringQuery { get; set; }
     }
 }
diff --git a/test/TestServerProjectsLowLevel/url/src/Generated/PathItemsClient.cs b/test/TestServerProjectsLowLevel/url/src/Generated/PathItemsClient.cs
index c645a5a7093..ff7724440d1 100644
--- a/test/TestServerProjectsLowLevel/url/src/Generated/PathItemsClient.cs
+++ b/test/TestServerProjectsLowLevel/url/src/Generated/PathItemsClient.cs
@@ -40,7 +40,7 @@ protected PathItemsClient()
         /// <param name="credential"> A credential used to authenticate to an Azure Service. </param>
         /// <exception cref="ArgumentNullException"> <paramref name="globalStringPath"/> or <paramref name="credential"/> is null. </exception>
         /// <exception cref="ArgumentException"> <paramref name="globalStringPath"/> is an empty string, and was expected to be non-empty. </exception>
-        public PathItemsClient(string globalStringPath, AzureKeyCredential credential) : this(new Uri("http://localhost:3000"), globalStringPath, credential, null, new AutoRestUrlTestServiceClientOptions())
+        public PathItemsClient(string globalStringPath, AzureKeyCredential credential) : this(new Uri("http://localhost:3000"), globalStringPath, credential, new AutoRestUrlTestServiceClientOptions())
         {
         }
 
@@ -48,11 +48,10 @@ protected PathItemsClient()
         /// <param name="endpoint"> server parameter. </param>
         /// <param name="globalStringPath"> A string value 'globalItemStringPath' that appears in the path. </param>
         /// <param name="credential"> A credential used to authenticate to an Azure Service. </param>
-        /// <param name="globalStringQuery"> should contain value null. </param>
         /// <param name="options"> The options for configuring the client. </param>
         /// <exception cref="ArgumentNullException"> <paramref name="endpoint"/>, <paramref name="globalStringPath"/> or <paramref name="credential"/> is null. </exception>
         /// <exception cref="ArgumentException"> <paramref name="globalStringPath"/> is an empty string, and was expected to be non-empty. </exception>
-        public PathItemsClient(Uri endpoint, string globalStringPath, AzureKeyCredential credential, string globalStringQuery, AutoRestUrlTestServiceClientOptions options)
+        public PathItemsClient(Uri endpoint, string globalStringPath, AzureKeyCredential credential, AutoRestUrlTestServiceClientOptions options)
         {
             Argument.AssertNotNull(endpoint, nameof(endpoint));
             Argument.AssertNotNullOrEmpty(globalStringPath, nameof(globalStringPath));
@@ -64,7 +63,7 @@ public PathItemsClient(Uri endpoint, string globalStringPath, AzureKeyCredential
             _pipeline = HttpPipelineBuilder.Build(options, Array.Empty<HttpPipelinePolicy>(), new HttpPipelinePolicy[] { new AzureKeyCredentialPolicy(_keyCredential, AuthorizationHeader) }, new ResponseClassifier());
             _globalStringPath = globalStringPath;
             _endpoint = endpoint;
-            _globalStringQuery = globalStringQuery;
+            _globalStringQuery = options.GlobalStringQuery;
         }
 
         /// <summary>
diff --git a/test/TestServerProjectsLowLevel/url/src/Generated/UrlLowLevelClientBuilderExtensions.cs b/test/TestServerProjectsLowLevel/url/src/Generated/UrlLowLevelClientBuilderExtensions.cs
index faabbf859fd..4b92e9a718f 100644
--- a/test/TestServerProjectsLowLevel/url/src/Generated/UrlLowLevelClientBuilderExtensions.cs
+++ b/test/TestServerProjectsLowLevel/url/src/Generated/UrlLowLevelClientBuilderExtensions.cs
@@ -40,11 +40,10 @@ public static IAzureClientBuilder<QueriesClient, AutoRestUrlTestServiceClientOpt
         /// <param name="endpoint"> server parameter. </param>
         /// <param name="globalStringPath"> A string value 'globalItemStringPath' that appears in the path. </param>
         /// <param name="credential"> A credential used to authenticate to an Azure Service. </param>
-        /// <param name="globalStringQuery"> should contain value null. </param>
-        public static IAzureClientBuilder<PathItemsClient, AutoRestUrlTestServiceClientOptions> AddPathItemsClient<TBuilder>(this TBuilder builder, Uri endpoint, string globalStringPath, AzureKeyCredential credential, string globalStringQuery)
+        public static IAzureClientBuilder<PathItemsClient, AutoRestUrlTestServiceClientOptions> AddPathItemsClient<TBuilder>(this TBuilder builder, Uri endpoint, string globalStringPath, AzureKeyCredential credential)
         where TBuilder : IAzureClientFactoryBuilder
         {
-            return builder.RegisterClientFactory<PathItemsClient, AutoRestUrlTestServiceClientOptions>((options) => new PathItemsClient(endpoint, globalStringPath, credential, globalStringQuery, options));
+            return builder.RegisterClientFactory<PathItemsClient, AutoRestUrlTestServiceClientOptions>((options) => new PathItemsClient(endpoint, globalStringPath, credential, options));
         }
 
         /// <summary> Registers a <see cref="PathsClient"/> instance. </summary>