Remove manual default extraction and update test to use positional record

Removed the manual default value extraction code from BuildRequestSchema
and SetDefaultValue helper as this should be handled by AIJsonUtilities.
Updated FormWithDefaults to be a positional record with optional parameters.
Test is now skipped until AIJsonUtilities supports extracting defaults from
optional parameters.

Co-authored-by: eiriktsarpalis <2813363+eiriktsarpalis@users.noreply.github.com>

Author: Copilot

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

@@ -307,52 +307,12 @@ private static ElicitRequestParams.RequestSchema BuildRequestSchema(Type type, J
         foreach (JsonPropertyInfo pi in typeInfo.Properties)
         {
             var def = CreatePrimitiveSchema(pi.PropertyType, serializerOptions);
-            
-            // Extract default value from DefaultValueAttribute if present
-            if (pi.AttributeProvider != null)
-            {
-                var attrs = pi.AttributeProvider.GetCustomAttributes(typeof(System.ComponentModel.DefaultValueAttribute), false);
-                if (attrs.Length > 0 && attrs[0] is System.ComponentModel.DefaultValueAttribute defaultValueAttr)
-                {
-                    SetDefaultValue(def, defaultValueAttr.Value);
-                }
-            }
-            
             props[pi.Name] = def;
         }
 
         return schema;
     }
 
-    /// <summary>
-    /// Sets the default value on a primitive schema definition based on the value type.
-    /// </summary>
-    /// <param name="schema">The schema to set the default value on.</param>
-    /// <param name="value">The default value.</param>
-    private static void SetDefaultValue(ElicitRequestParams.PrimitiveSchemaDefinition schema, object? value)
-    {
-        if (value == null)
-        {
-            return;
-        }
-
-        switch (schema)
-        {
-            case ElicitRequestParams.StringSchema stringSchema:
-                stringSchema.Default = value.ToString();
-                break;
-            case ElicitRequestParams.NumberSchema numberSchema:
-                numberSchema.Default = Convert.ToDouble(value);
-                break;
-            case ElicitRequestParams.BooleanSchema booleanSchema:
-                booleanSchema.Default = Convert.ToBoolean(value);
-                break;
-            case ElicitRequestParams.EnumSchema enumSchema:
-                enumSchema.Default = value.ToString();
-                break;
-        }
-    }
-
     /// <summary>
     /// Creates a primitive schema definition for the specified type, if supported.
     /// </summary>

tests/ModelContextProtocol.Tests/Protocol/ElicitationTypedTests.cs

@@ -374,29 +374,19 @@ public sealed class Nested
     [JsonSerializable(typeof(JsonElement))]
     internal partial class ElicitationUnsupportedJsonContext : JsonSerializerContext;
 
-    public sealed class FormWithDefaults
-    {
-        [System.ComponentModel.DefaultValue("John Doe")]
-        public string Name { get; set; } = "John Doe";
-        
-        [System.ComponentModel.DefaultValue(30)]
-        public int Age { get; set; } = 30;
-        
-        [System.ComponentModel.DefaultValue(85.5)]
-        public double Score { get; set; } = 85.5;
-        
-        [System.ComponentModel.DefaultValue(true)]
-        public bool IsActive { get; set; } = true;
-        
-        [System.ComponentModel.DefaultValue("active")]
-        public string Status { get; set; } = "active";
-    }
+    public sealed record FormWithDefaults(
+        string Name = "John Doe",
+        int Age = 30,
+        double Score = 85.5,
+        bool IsActive = true,
+        string Status = "active"
+    );
 
     [JsonSerializable(typeof(FormWithDefaults))]
     [JsonSerializable(typeof(JsonElement))]
     internal partial class ElicitationDefaultsJsonContext : JsonSerializerContext;
 
-    [Fact]
+    [Fact(Skip = "Requires AIJsonUtilities to support extracting default values from optional parameters")]
     public async Task Elicit_Typed_With_Defaults_Maps_To_Schema_Defaults()
     {
         await using McpClient client = await CreateMcpClientForServer(new McpClientOptions