Add ToolAnnotations support (#124)

* Add ToolAnnotations support

* Address feedback

Author: stephentoub

samples/AspNetCoreSseServer/Tools/SampleLlmTool.cs

@@ -10,7 +10,7 @@ namespace TestServerWithHosting.Tools;
 [McpServerToolType]
 public static class SampleLlmTool
 {
-    [McpServerTool("sampleLLM"), Description("Samples from an LLM using MCP's sampling feature")]
+    [McpServerTool(Name = "sampleLLM"), Description("Samples from an LLM using MCP's sampling feature")]
     public static async Task<string> SampleLLM(
         IMcpServer thisServer,
         [Description("The prompt to send to the LLM")] string prompt,

samples/TestServerWithHosting/Tools/SampleLlmTool.cs

@@ -10,7 +10,7 @@ namespace TestServerWithHosting.Tools;
 [McpServerToolType]
 public static class SampleLlmTool
 {
-    [McpServerTool("sampleLLM"), Description("Samples from an LLM using MCP's sampling feature")]
+    [McpServerTool(Name = "sampleLLM"), Description("Samples from an LLM using MCP's sampling feature")]
     public static async Task<string> SampleLLM(
         IMcpServer thisServer,
         [Description("The prompt to send to the LLM")] string prompt,

src/ModelContextProtocol/AIContentExtensions.cs

@@ -33,7 +33,7 @@ public static AIContent ToAIContent(this Content content)
         Throw.IfNull(content);
 
         AIContent ac;
-        if (content is { Type: "image", MimeType: not null, Data: not null })
+        if (content is { Type: "image" or "audio", MimeType: not null, Data: not null })
         {
             ac = new DataContent(Convert.FromBase64String(content.Data), content.MimeType);
         }
@@ -112,6 +112,7 @@ internal static Content ToContent(this AIContent content) =>
                 Text = textContent.Text,
                 Type = "text",
             },
+
             DataContent dataContent => new()
             {
                 Data = dataContent.GetBase64Data(),
@@ -121,6 +122,7 @@ internal static Content ToContent(this AIContent content) =>
                     dataContent.HasTopLevelMediaType("audio") ? "audio" :
                     "resource",
             },
+            
             _ => new()
             {
                 Text = JsonSerializer.Serialize(content, McpJsonUtilities.DefaultOptions.GetTypeInfo(typeof(object))),

src/ModelContextProtocol/Client/McpClientExtensions.cs

@@ -469,7 +469,7 @@ internal static (IList<ChatMessage> Messages, ChatOptions? Options) ToChatClient
             {
                 message.Contents.Add(new TextContent(sm.Content.Text));
             }
-            else if (sm.Content is { Type: "image", MimeType: not null, Data: not null })
+            else if (sm.Content is { Type: "image" or "audio", MimeType: not null, Data: not null })
             {
                 message.Contents.Add(new DataContent(Convert.FromBase64String(sm.Content.Data), sm.Content.MimeType));
             }
@@ -512,11 +512,11 @@ internal static CreateMessageResult ToCreateMessageResult(this ChatResponse chat
         {
             foreach (var lmc in lastMessage.Contents)
             {
-                if (lmc is DataContent dc && dc.HasTopLevelMediaType("image"))
+                if (lmc is DataContent dc && (dc.HasTopLevelMediaType("image") || dc.HasTopLevelMediaType("audio")))
                 {
                     content = new()
                     {
-                        Type = "image",
+                        Type = dc.HasTopLevelMediaType("image") ? "image" : "audio",
                         MimeType = dc.MediaType,
                         Data = dc.GetBase64Data(),
                     };

src/ModelContextProtocol/Client/McpClientTool.cs

@@ -9,22 +9,24 @@ namespace ModelContextProtocol.Client;
 public sealed class McpClientTool : AIFunction
 {
     private readonly IMcpClient _client;
-    private readonly Tool _tool;
 
     internal McpClientTool(IMcpClient client, Tool tool)
     {
         _client = client;
-        _tool = tool;
+        ProtocolTool = tool;
     }
 
+    /// <summary>Gets the protocol <see cref="Tool"/> type for this instance.</summary>
+    public Tool ProtocolTool { get; }
+
     /// <inheritdoc/>
-    public override string Name => _tool.Name;
+    public override string Name => ProtocolTool.Name;
 
     /// <inheritdoc/>
-    public override string Description => _tool.Description ?? string.Empty;
+    public override string Description => ProtocolTool.Description ?? string.Empty;
 
     /// <inheritdoc/>
-    public override JsonElement JsonSchema => _tool.InputSchema;
+    public override JsonElement JsonSchema => ProtocolTool.InputSchema;
 
     /// <inheritdoc/>
     public override JsonSerializerOptions JsonSerializerOptions => McpJsonUtilities.DefaultOptions;
@@ -37,7 +39,7 @@ internal McpClientTool(IMcpClient client, Tool tool)
             arguments as IReadOnlyDictionary<string, object?> ??
             arguments.ToDictionary();
 
-        CallToolResponse result = await _client.CallToolAsync(_tool.Name, argDict, cancellationToken).ConfigureAwait(false);
+        CallToolResponse result = await _client.CallToolAsync(ProtocolTool.Name, argDict, cancellationToken).ConfigureAwait(false);
         return JsonSerializer.SerializeToElement(result, McpJsonUtilities.JsonContext.Default.CallToolResponse);
     }
 }

src/ModelContextProtocol/Configuration/McpServerBuilderExtensions.Tools.cs

@@ -37,14 +37,9 @@ public static partial class McpServerBuilderExtensions
         {
             if (toolMethod.GetCustomAttribute<McpServerToolAttribute>() is not null)
             {
-                if (toolMethod.IsStatic)
-                {
-                    builder.Services.AddSingleton(services => McpServerTool.Create(toolMethod, services: services));
-                }
-                else
-                {
-                    builder.Services.AddSingleton(services => McpServerTool.Create(toolMethod, typeof(TTool), services: services));
-                }
+                builder.Services.AddSingleton((Func<IServiceProvider, McpServerTool>)(toolMethod.IsStatic ?
+                    services => McpServerTool.Create(toolMethod, new McpServerToolCreateOptions() { Services = services }) :
+                    services => McpServerTool.Create(toolMethod, typeof(TTool), new() { Services = services })));
             }
         }
 
@@ -71,18 +66,13 @@ public static IMcpServerBuilder WithTools(this IMcpServerBuilder builder, params
         {
             if (toolType is not null)
             {
-                foreach (var method in toolType.GetMethods(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance))
+                foreach (var toolMethod in toolType.GetMethods(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance))
                 {
-                    if (method.GetCustomAttribute<McpServerToolAttribute>() is not null)
+                    if (toolMethod.GetCustomAttribute<McpServerToolAttribute>() is not null)
                     {
-                        if (method.IsStatic)
-                        {
-                            builder.Services.AddSingleton(services => McpServerTool.Create(method, services: services));
-                        }
-                        else
-                        {
-                            builder.Services.AddSingleton(services => McpServerTool.Create(method, toolType, services: services));
-                        }
+                        builder.Services.AddSingleton((Func<IServiceProvider, McpServerTool>)(toolMethod.IsStatic ?
+                            services => McpServerTool.Create(toolMethod, new McpServerToolCreateOptions() { Services = services }) :
+                            services => McpServerTool.Create(toolMethod, toolType, new() { Services = services })));
                     }
                 }
             }

src/ModelContextProtocol/Protocol/Transport/StdioServerTransport.cs

@@ -25,7 +25,7 @@ public sealed class StdioServerTransport : TransportBase, IServerTransport
     private readonly TextReader _stdInReader;
     private readonly Stream _stdOutStream;
 
-    private SemaphoreSlim _sendLock = new(1, 1);
+    private readonly SemaphoreSlim _sendLock = new(1, 1);
     private Task? _readTask;
     private CancellationTokenSource? _shutdownCts;
 

src/ModelContextProtocol/Protocol/Types/Annotated.cs

@@ -4,7 +4,7 @@ namespace ModelContextProtocol.Protocol.Types;
 
 /// <summary>
 /// Base for objects that include optional annotations for the client. The client can use annotations to inform how objects are used or displayed.
-/// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
+/// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">See the schema for details</see>
 /// </summary>
 public abstract record Annotated
 {

src/ModelContextProtocol/Protocol/Types/Annotations.cs

@@ -4,7 +4,7 @@ namespace ModelContextProtocol.Protocol.Types;
 
 /// <summary>
 /// Represents annotations that can be attached to content.
-/// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
+/// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">See the schema for details</see>
 /// </summary>
 public record Annotations
 {

src/ModelContextProtocol/Protocol/Types/Argument.cs

@@ -4,7 +4,7 @@ namespace ModelContextProtocol.Protocol.Types;
 
 /// <summary>
 /// Used for completion requests to provide additional context for the completion options.
-/// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
+/// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">See the schema for details</see>
 /// </summary>
 public class Argument
 {