Use DescriptionAttribute and HasDefaultValue in server builder extensions (#46)

samples/TestServerWithHosting/Tools/EchoTool.cs

@@ -1,12 +1,13 @@
 using McpDotNet.Server;
+using System.ComponentModel;
 
 namespace TestServerWithHosting.Tools;
 
 [McpToolType]
 public static class EchoTool
 {
-    [McpTool(description: "Echoes the input back to the client.")]
+    [McpTool, Description("Echoes the input back to the client.")]
-    public static string Echo([McpParameter(true)] string message)
+    public static string Echo(string message)
     {
         return "hello " + message;
     }

samples/TestServerWithHosting/Tools/SampleLlmTool.cs

@@ -1,5 +1,6 @@
 using McpDotNet.Protocol.Types;
 using McpDotNet.Server;
+using System.ComponentModel;
 
 namespace TestServerWithHosting.Tools;
 
@@ -16,10 +17,10 @@ public class SampleLlmTool
         _server = server ?? throw new ArgumentNullException(nameof(server));
     }
 
-    [McpTool(name: "sampleLLM", description: "Samples from an LLM using MCP's sampling feature")]
+    [McpTool("sampleLLM"), Description("Samples from an LLM using MCP's sampling feature")]
     public async Task<string> SampleLLM(
-        [McpParameter(true, description: "The prompt to send to the LLM")] string prompt,
+        [Description("The prompt to send to the LLM")] string prompt,
-        [McpParameter(true, description: "Maximum number of tokens to generate")] int maxTokens,
+        [Description("Maximum number of tokens to generate")] int maxTokens,
         CancellationToken cancellationToken)
     {
         var samplingParams = CreateRequestSamplingParams(prompt ?? string.Empty, "sampleLLM", maxTokens);

src/mcpdotnet/Configuration/McpServerBuilderExtensions.Tools.cs

@@ -1,4 +1,5 @@
-using System.Globalization;
+using System.ComponentModel;
+using System.Globalization;
 using System.Reflection;
 using System.Text.Json;
 using McpDotNet.Configuration;
@@ -117,7 +118,7 @@ public static partial class McpServerBuilderExtensions
         return WithTools(builder, toolTypes.ToArray());
     }
 
-    private static Tool CreateTool(MethodInfo method, McpToolAttribute attribute)
+    private static Tool CreateTool(MethodInfo method, McpToolAttribute mcpAttribute)
     {
         Dictionary<string, JsonSchemaProperty> properties = [];
         List<string>? requiredProperties = null;
@@ -127,15 +128,15 @@ public static partial class McpServerBuilderExtensions
             if (parameter.ParameterType == typeof(CancellationToken))
                 continue;
 
-            var parameterAttribute = parameter.GetCustomAttribute<McpParameterAttribute>();
+            var parameterDescriptionAttr = parameter.GetCustomAttribute<DescriptionAttribute>();
 
             properties.Add(parameter.Name ?? "NoName", new JsonSchemaProperty()
             {
                 Type = GetParameterType(parameter.ParameterType),
-                Description = parameterAttribute?.Description
+                Description = parameterDescriptionAttr?.Description,
             });
 
-            if (parameterAttribute?.Required == true)
+            if (!parameter.HasDefaultValue)
             {
                 requiredProperties ??= [];
                 requiredProperties.Add(parameter.Name ?? "NoName");
@@ -144,8 +145,8 @@ public static partial class McpServerBuilderExtensions
 
         return new Tool()
         {
-            Name = attribute.Name ?? method.Name,
+            Name = mcpAttribute.Name ?? method.Name,
-            Description = attribute.Description,
+            Description = method.GetCustomAttribute<DescriptionAttribute>()?.Description,
             InputSchema = new JsonSchema()
             {
                 Type = "object",
@@ -229,12 +230,10 @@ public static partial class McpServerBuilderExtensions
             }
             else
             {
-                var parameterAttribute = parameter.GetCustomAttribute<McpParameterAttribute>();
+                if (!parameter.HasDefaultValue)
-
-                if (parameterAttribute?.Required == true)
                     throw new McpServerException($"Missing required argument '{parameter.Name}'.");
 
-                parameters.Add(parameter.HasDefaultValue ? parameter.DefaultValue : null);
+                parameters.Add(parameter.DefaultValue);
             }
         }
 

src/mcpdotnet/Server/McpParameterAttribute.cs

@@ -1,29 +0,0 @@
-namespace McpDotNet.Server;
-
-/// <summary>
-/// Attribute to mark a method parameter
-/// </summary>
-[AttributeUsage(AttributeTargets.Parameter)]
-public sealed class McpParameterAttribute : Attribute
-{
-    /// <summary>
-    /// Defines if the parameter is required.
-    /// </summary>
-    public bool Required { get; }
-
-    /// <summary>
-    /// A description of the parameter.
-    /// </summary>
-    public string? Description { get; }
-
-    /// <summary>
-    /// Attribute to mark a method as an MCP tool.
-    /// </summary>
-    /// <param name="required">True if the parameter is mandatory.</param>
-    /// <param name="description">A description of the tool.</param>
-    public McpParameterAttribute(bool required = false, string? description = null)
-    {
-        Required = required;
-        Description = description;
-    }
-}

src/mcpdotnet/Server/McpToolAttribute.cs

@@ -6,22 +6,15 @@
 [AttributeUsage(AttributeTargets.Method)]
 public sealed class McpToolAttribute : Attribute
 {
-    /// The name of the tool. If not provided, the class name will be used.  
+    /// <summary>Gets the name of the tool.</summary>
+    /// <remarks>If not provided, the method name will be used.</remarks>
     public string? Name { get; }
-
-    /// <summary>
-    /// A description of the tool.
-    /// </summary>
-    public string? Description { get; }
-
     /// <summary>
     /// Attribute to mark a method as an MCP tool.
     /// </summary>
     /// <param name="name">The name of the tool. If not provided, the class name will be used.</param>
-    /// <param name="description">A description of the tool.</param>
+    public McpToolAttribute(string? name = null)
-    public McpToolAttribute(string? name = null, string? description = null)
     {
         Name = name;
-        Description = description;
     }
 }

tests/mcpdotnet.Tests/McpServerBuilderExtensionsToolsTests.cs

@@ -3,6 +3,7 @@ using McpDotNet.Server;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;
 using Moq;
+using System.ComponentModel;
 
 namespace McpDotNet.Tests;
 
@@ -131,14 +132,14 @@ public class McpServerBuilderExtensionsToolsTests
 
     private static class EchoTool
     {
-        [McpTool(description: "Echoes the input back to the client.")]
+        [McpTool, Description("Echoes the input back to the client.")]
-        public static string Echo([McpParameter(true, description: "the echoes message")] string message)
+        public static string Echo([Description("the echoes message")] string message)
         {
             return "hello " + message;
         }
 
-        [McpTool(name: "double_echo", description: "Echoes the input back to the client.")]
+        [McpTool("double_echo"), Description("Echoes the input back to the client.")]
-        public static string Echo2([McpParameter(true)] string message)
+        public static string Echo2(string message)
         {
             return "hello hello" + message;
         }
@@ -154,8 +155,8 @@ public class McpServerBuilderExtensionsToolsTests
         {
         }
 
-        [McpTool(description: "Echoes the input back to the client.")]
+        [McpTool, Description("Echoes the input back to the client.")]
-        public Task<string> Echo([McpParameter(true)] string message)
+        public Task<string> Echo(string message)
         {
             return Task.FromResult("hello " + message);
         }