Clean build

Author: mikekistler

samples/EverythingServer/Tools/SampleLlmTool.cs

@@ -15,7 +15,7 @@ public static async Task<string> SampleLLM(
         CancellationToken cancellationToken)
     {
         var samplingParams = CreateRequestSamplingParams(prompt ?? string.Empty, "sampleLLM", maxTokens);
-        var sampleResult = await server.SampleAsync(samplingParams, meta: null, cancellationToken);
+        var sampleResult = await server.SampleAsync(samplingParams, options: null, cancellationToken);
 
         return $"LLM sampling result: {sampleResult.Content.OfType<TextContentBlock>().FirstOrDefault()?.Text}";
     }

samples/TestServerWithHosting/Tools/SampleLlmTool.cs

@@ -18,7 +18,7 @@ public static async Task<string> SampleLLM(
         CancellationToken cancellationToken)
     {
         var samplingParams = CreateRequestSamplingParams(prompt ?? string.Empty, "sampleLLM", maxTokens);
-        var sampleResult = await thisServer.SampleAsync(samplingParams, meta: null, cancellationToken);
+        var sampleResult = await thisServer.SampleAsync(samplingParams, options: null, cancellationToken);
 
         return $"LLM sampling result: {sampleResult.Content.OfType<TextContentBlock>().FirstOrDefault()?.Text}";
     }

src/ModelContextProtocol.Core/Client/McpClient.Methods.cs

@@ -98,6 +98,6 @@ public async ValueTask<GetPromptResult> GetAsync(
             arguments as IReadOnlyDictionary<string, object?> ??
             arguments?.ToDictionary();
 
-        return await _client.GetPromptAsync(ProtocolPrompt.Name, argDict, null, serializerOptions, cancellationToken: cancellationToken).ConfigureAwait(false);
+        return await _client.GetPromptAsync(ProtocolPrompt.Name, argDict, new RequestOptions(null, serializerOptions), cancellationToken).ConfigureAwait(false);
     }
 }

src/ModelContextProtocol.Core/Client/McpClientPrompt.cs

@@ -80,7 +80,7 @@ public McpClientResource(McpClient client, Resource resource)
     /// <returns>A <see cref="ValueTask{ReadResourceResult}"/> containing the resource's result with content and messages.</returns>
     /// <remarks>
     /// <para>
-    /// This is a convenience method that internally calls <see cref="McpClient.ReadResourceAsync(string, System.Text.Json.Nodes.JsonObject, CancellationToken)"/>.
+    /// This is a convenience method that internally calls <see cref="McpClient.ReadResourceAsync(string, RequestOptions, CancellationToken)"/>.
     /// </para>
     /// </remarks>
     public ValueTask<ReadResourceResult> ReadAsync(

src/ModelContextProtocol.Core/Client/McpClientResource.cs

@@ -194,7 +194,15 @@ public ValueTask<CallToolResult> CallAsync(
         IProgress<ProgressNotificationValue>? progress = null,
         JsonSerializerOptions? serializerOptions = null,
         CancellationToken cancellationToken = default) =>
-        _client.CallToolAsync(ProtocolTool.Name, arguments, progress, null, serializerOptions, cancellationToken);
+        _client.CallToolAsync(
+            ProtocolTool.Name,
+            arguments,
+            progress,
+            new RequestOptions
+            {
+                JsonSerializerOptions = serializerOptions
+            },
+            cancellationToken);
 
     /// <summary>
     /// Creates a new instance of the tool but modified to return the specified name from its <see cref="Name"/> property.

src/ModelContextProtocol.Core/Client/McpClientTool.cs

@@ -152,7 +152,7 @@ internal Task SendNotificationAsync<TParameters>(
     /// </summary>
     /// <param name="progressToken">The <see cref="ProgressToken"/> identifying the operation for which progress is being reported.</param>
     /// <param name="progress">The progress update to send, containing information such as percentage complete or status message.</param>
-    /// <param name="meta">Optional metadata to include in the notification.</param>
+    /// <param name="options">Optional request options including metadata, serialization settings, and progress tracking.</param>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A task representing the completion of the notification operation (not the operation being tracked).</returns>
     /// <exception cref="ArgumentNullException">The current session instance is <see langword="null"/>.</exception>
@@ -169,7 +169,7 @@ internal Task SendNotificationAsync<TParameters>(
     public Task NotifyProgressAsync(
         ProgressToken progressToken,
         ProgressNotificationValue progress,
-        JsonObject? meta = null,
+        RequestOptions? options = null,
         CancellationToken cancellationToken = default)
     {
         return SendNotificationAsync(
@@ -178,7 +178,7 @@ public Task NotifyProgressAsync(
             {
                 ProgressToken = progressToken,
                 Progress = progress,
-                Meta = meta,
+                Meta = options?.Meta,
             },
             McpJsonUtilities.JsonContext.Default.ProgressNotificationParams,
             cancellationToken);

src/ModelContextProtocol.Core/McpSession.Methods.cs

@@ -0,0 +1,60 @@
+using System.Text.Json;
+using System.Text.Json.Nodes;
+using ModelContextProtocol.Protocol;
+
+namespace ModelContextProtocol;
+
+/// <summary>
+/// Contains optional parameters for MCP requests.
+/// </summary>
+public sealed class RequestOptions
+{
+    /// <summary>
+    /// Gets or sets optional metadata to include in the request.
+    /// </summary>
+    public JsonObject? Meta { get; set; }
+
+    /// <summary>
+    /// Gets or sets the JSON serializer options to use for serialization and deserialization.
+    /// </summary>
+    public JsonSerializerOptions? JsonSerializerOptions { get; set; }
+
+    /// <summary>
+    /// Gets or sets the progress token for tracking long-running operations.
+    /// </summary>
+    public ProgressToken? ProgressToken { get; set; }
+
+    /// <summary>
+    /// Gets a default instance with all properties set to null.
+    /// </summary>
+    public static RequestOptions Default { get; } = new();
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="RequestOptions"/> class.
+    /// </summary>
+    public RequestOptions()
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="RequestOptions"/> class with the specified metadata.
+    /// </summary>
+    /// <param name="meta">Optional metadata to include in the request.</param>
+    public RequestOptions(JsonObject? meta)
+    {
+        Meta = meta;
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="RequestOptions"/> class with the specified options.
+    /// </summary>
+    /// <param name="meta">Optional metadata to include in the request.</param>
+    /// <param name="jsonSerializerOptions">The JSON serializer options to use.</param>
+    /// <param name="progressToken">The progress token for tracking operations.</param>
+    public RequestOptions(JsonObject? meta = null, JsonSerializerOptions? jsonSerializerOptions = null, ProgressToken? progressToken = null)
+    {
+        Meta = meta;
+        JsonSerializerOptions = jsonSerializerOptions;
+        ProgressToken = progressToken;
+    }
+}

src/ModelContextProtocol.Core/RequestOptions.cs

@@ -51,18 +51,18 @@ public static McpServer Create(
     /// Requests to sample an LLM via the client using the specified request parameters.
     /// </summary>
     /// <param name="request">The parameters for the sampling request.</param>
-    /// <param name="meta">Optional metadata to include in the request.</param>
+    /// <param name="options">Optional request options including metadata, serialization settings, and progress tracking.</param>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests.</param>
     /// <returns>A task containing the sampling result from the client.</returns>
     /// <exception cref="InvalidOperationException">The client does not support sampling.</exception>
     public ValueTask<CreateMessageResult> SampleAsync(
-        CreateMessageRequestParams request, JsonObject? meta = null, CancellationToken cancellationToken = default)
+        CreateMessageRequestParams request, RequestOptions? options = null, CancellationToken cancellationToken = default)
     {
         ThrowIfSamplingUnsupported();
 
-        if (meta is not null)
+        if (options?.Meta is not null)
         {
-            request.Meta = meta;
+            request.Meta = options.Meta;
         }
 
         return SendRequestAsync(
@@ -223,18 +223,18 @@ public ILoggerProvider AsClientLoggerProvider()
     /// Requests the client to list the roots it exposes.
     /// </summary>
     /// <param name="request">The parameters for the list roots request.</param>
-    /// <param name="meta">Optional metadata to include in the request.</param>
+    /// <param name="options">Optional request options including metadata, serialization settings, and progress tracking.</param>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests.</param>
     /// <returns>A task containing the list of roots exposed by the client.</returns>
     /// <exception cref="InvalidOperationException">The client does not support roots.</exception>
     public ValueTask<ListRootsResult> RequestRootsAsync(
-        ListRootsRequestParams request, JsonObject? meta = null, CancellationToken cancellationToken = default)
+        ListRootsRequestParams request, RequestOptions? options = null, CancellationToken cancellationToken = default)
     {
         ThrowIfRootsUnsupported();
 
-        if (meta is not null)
+        if (options?.Meta is not null)
         {
-            request.Meta = meta;
+            request.Meta = options.Meta;
         }
 
         return SendRequestAsync(
@@ -488,7 +488,7 @@ private sealed class SamplingChatClient(McpServer server) : IChatClient
 
         /// <inheritdoc/>
         public Task<ChatResponse> GetResponseAsync(IEnumerable<ChatMessage> messages, ChatOptions? options = null, CancellationToken cancellationToken = default) =>
-            _server.SampleAsync(messages, options, meta: null, cancellationToken);
+            _server.SampleAsync(messages, options, requestOptions: null, cancellationToken);
 
         /// <inheritdoc/>
         async IAsyncEnumerable<ChatResponseUpdate> IChatClient.GetStreamingResponseAsync(

src/ModelContextProtocol.Core/Server/McpServer.Methods.cs

@@ -21,7 +21,7 @@ public sealed class McpServerOptions
     /// </summary>
     /// <remarks>
     /// These determine which features will be available when a client connects.
-    /// Capabilities can include "tools", "prompts", "resources", "logging", and other 
+    /// Capabilities can include "tools", "prompts", "resources", "logging", and other
     /// protocol-specific functionality.
     /// </remarks>
     public ServerCapabilities? Capabilities { get; set; }
@@ -84,21 +84,21 @@ public sealed class McpServerOptions
     /// Gets the filter collections for MCP server handlers.
     /// </summary>
     /// <remarks>
-    /// This property provides access to filter collections that can be used to modify the behavior 
-    /// of various MCP server handlers. Filters are applied in reverse order, so the last filter 
+    /// This property provides access to filter collections that can be used to modify the behavior
+    /// of various MCP server handlers. Filters are applied in reverse order, so the last filter
     /// added will be the outermost (first to execute).
     /// </remarks>
     public McpServerFilters Filters { get; } = new();
 
     /// <summary>
     /// Gets or sets the container of handlers used by the server for processing protocol messages.
     /// </summary>
-    public McpServerHandlers Handlers 
-    { 
+    public McpServerHandlers Handlers
+    {
         get => field ??= new();
         set
-        { 
-            Throw.IfNull(value); 
+        {
+            Throw.IfNull(value);
             field = value;
         }
     }
@@ -143,7 +143,7 @@ public McpServerHandlers Handlers
     /// when those are provided:
     /// </para>
     /// <para>
-    /// - For <see cref="RequestMethods.PromptsList"/> requests: The server returns all prompts from this collection 
+    /// - For <see cref="RequestMethods.PromptsList"/> requests: The server returns all prompts from this collection
     ///   plus any additional prompts provided by the <see cref="McpServerHandlers.ListPromptsHandler"/> if it's set.
     /// </para>
     /// <para>
@@ -158,7 +158,7 @@ public McpServerHandlers Handlers
     /// </summary>
     /// <remarks>
     /// <para>
-    /// This value is used in <see cref="McpServer.SampleAsync(IEnumerable{Microsoft.Extensions.AI.ChatMessage}, Microsoft.Extensions.AI.ChatOptions?, System.Text.Json.Nodes.JsonObject?, CancellationToken)"/>
+    /// This value is used in <see cref="McpServer.SampleAsync(IEnumerable{Microsoft.Extensions.AI.ChatMessage}, Microsoft.Extensions.AI.ChatOptions?, RequestOptions?, CancellationToken)"/>
     /// when <see cref="Microsoft.Extensions.AI.ChatOptions.MaxOutputTokens"/> is not set in the request options.
     /// </para>
     /// <para>