Fix UnderlyingMethod property path, use SerializerOptions, and fix JsonObject cref

Co-authored-by: stephentoub <[email protected]>

Author: Copilot

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerPrompt.cs

@@ -140,10 +140,10 @@ private static AIFunctionFactoryOptions CreateAIFunctionFactoryOptions(
         };
 
         // Populate Meta from options and/or McpMetaAttribute instances if a MethodInfo is available
-        MethodInfo? method = options?.Metadata?.FirstOrDefault(m => m is MethodInfo) as MethodInfo ?? function.Metadata?.UnderlyingMethod;
+        MethodInfo? method = options?.Metadata?.FirstOrDefault(m => m is MethodInfo) as MethodInfo ?? function.UnderlyingMethod;
         if (method is not null)
         {
-            prompt.Meta = AIFunctionMcpServerTool.CreateMetaFromAttributes(method, options?.Meta);
+            prompt.Meta = AIFunctionMcpServerTool.CreateMetaFromAttributes(method, options?.Meta, options?.SerializerOptions);
         }
         else if (options?.Meta is not null)
         {

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerResource.cs

@@ -213,11 +213,11 @@ private static AIFunctionFactoryOptions CreateAIFunctionFactoryOptions(
         string name = options?.Name ?? function.Name;
 
         // Populate Meta from options and/or McpMetaAttribute instances if a MethodInfo is available
-        MethodInfo? method = options?.Metadata?.FirstOrDefault(m => m is MethodInfo) as MethodInfo ?? function.Metadata?.UnderlyingMethod;
+        MethodInfo? method = options?.Metadata?.FirstOrDefault(m => m is MethodInfo) as MethodInfo ?? function.UnderlyingMethod;
         JsonObject? meta = null;
         if (method is not null)
         {
-            meta = AIFunctionMcpServerTool.CreateMetaFromAttributes(method, options?.Meta);
+            meta = AIFunctionMcpServerTool.CreateMetaFromAttributes(method, options?.Meta, options?.SerializerOptions);
         }
         else if (options?.Meta is not null)
         {

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerTool.cs

@@ -145,10 +145,10 @@ options.OpenWorld is not null ||
             }
 
             // Populate Meta from options and/or McpMetaAttribute instances if a MethodInfo is available
-            MethodInfo? method = options.Metadata?.FirstOrDefault(m => m is MethodInfo) as MethodInfo ?? function.Metadata?.UnderlyingMethod;
+            MethodInfo? method = options.Metadata?.FirstOrDefault(m => m is MethodInfo) as MethodInfo ?? function.UnderlyingMethod;
             if (method is not null)
             {
-                tool.Meta = CreateMetaFromAttributes(method, options.Meta);
+                tool.Meta = CreateMetaFromAttributes(method, options.Meta, options.SerializerOptions);
             }
             else if (options.Meta is not null)
             {
@@ -365,8 +365,9 @@ internal static IReadOnlyList<object> CreateMetadata(MethodInfo method)
     /// <summary>Creates a Meta JsonObject from McpMetaAttribute instances on the specified method.</summary>
     /// <param name="method">The method to extract McpMetaAttribute instances from.</param>
     /// <param name="seedMeta">Optional JsonObject to seed the Meta with. Properties from this object take precedence over attributes.</param>
+    /// <param name="serializerOptions">Optional JsonSerializerOptions to use for serialization. Defaults to McpJsonUtilities.DefaultOptions if not provided.</param>
     /// <returns>A JsonObject with metadata, or null if no metadata is present.</returns>
-    internal static JsonObject? CreateMetaFromAttributes(MethodInfo method, JsonObject? seedMeta = null)
+    internal static JsonObject? CreateMetaFromAttributes(MethodInfo method, JsonObject? seedMeta = null, JsonSerializerOptions? serializerOptions = null)
     {
         // Get all McpMetaAttribute instances from the method
         var metaAttributes = method.GetCustomAttributes<McpMetaAttribute>();
@@ -378,7 +379,7 @@ internal static IReadOnlyList<object> CreateMetadata(MethodInfo method)
             // Only add the attribute property if it doesn't already exist in the seed
             if (!meta.ContainsKey(attr.Name))
             {
-                meta[attr.Name] = JsonSerializer.SerializeToNode(attr.Value);
+                meta[attr.Name] = JsonSerializer.SerializeToNode(attr.Value, serializerOptions ?? McpJsonUtilities.DefaultOptions);
             }
         }
 

src/ModelContextProtocol.Core/Server/McpServerPromptCreateOptions.cs

@@ -91,9 +91,9 @@ public sealed class McpServerPromptCreateOptions
     /// </summary>
     /// <remarks>
     /// <para>
-    /// This JsonObject is used to seed the <see cref="Prompt.Meta"/> property. Any metadata from
+    /// This <see cref="System.Text.Json.Nodes.JsonObject"/> is used to seed the <see cref="Prompt.Meta"/> property. Any metadata from
     /// <see cref="McpMetaAttribute"/> instances on the method will be added to this object, but
-    /// properties already present in this JsonObject will not be overwritten.
+    /// properties already present in this <see cref="System.Text.Json.Nodes.JsonObject"/> will not be overwritten.
     /// </para>
     /// <para>
     /// Implementations must not make assumptions about its contents.

src/ModelContextProtocol.Core/Server/McpServerResourceCreateOptions.cs

@@ -106,9 +106,9 @@ public sealed class McpServerResourceCreateOptions
     /// </summary>
     /// <remarks>
     /// <para>
-    /// This JsonObject is used to seed the <see cref="Resource.Meta"/> property. Any metadata from
+    /// This <see cref="System.Text.Json.Nodes.JsonObject"/> is used to seed the <see cref="Resource.Meta"/> property. Any metadata from
     /// <see cref="McpMetaAttribute"/> instances on the method will be added to this object, but
-    /// properties already present in this JsonObject will not be overwritten.
+    /// properties already present in this <see cref="System.Text.Json.Nodes.JsonObject"/> will not be overwritten.
     /// </para>
     /// <para>
     /// Implementations must not make assumptions about its contents.

src/ModelContextProtocol.Core/Server/McpServerToolCreateOptions.cs

@@ -177,9 +177,9 @@ public sealed class McpServerToolCreateOptions
     /// </summary>
     /// <remarks>
     /// <para>
-    /// This JsonObject is used to seed the <see cref="Tool.Meta"/> property. Any metadata from
+    /// This <see cref="System.Text.Json.Nodes.JsonObject"/> is used to seed the <see cref="Tool.Meta"/> property. Any metadata from
     /// <see cref="McpMetaAttribute"/> instances on the method will be added to this object, but
-    /// properties already present in this JsonObject will not be overwritten.
+    /// properties already present in this <see cref="System.Text.Json.Nodes.JsonObject"/> will not be overwritten.
     /// </para>
     /// <para>
     /// Implementations must not make assumptions about its contents.