Update Microsoft.Extensions.AI version & expose JSON configuration on McpServerResourceCreateOptions (#511)

* Update Microsoft.Extensions.AI version

* Update Microsoft.Extensions.AI.OpenAI

* Fix failing tests; add JSON configuration options to McpServerResourceCreateOptions.

* Replace temporary code with `AIFunction.ReturnJsonSchema`

---------

Co-authored-by: Eirik Tsarpalis <eirik.tsarpalis@gmail.com>

Directory.Packages.props

@@ -3,7 +3,7 @@
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
     <System9Version>9.0.5</System9Version>
     <System10Version>10.0.0-preview.4.25258.110</System10Version>
-    <MicrosoftExtensionsAIVersion>9.5.0</MicrosoftExtensionsAIVersion>
+    <MicrosoftExtensionsAIVersion>9.6.0</MicrosoftExtensionsAIVersion>
   </PropertyGroup>
 
   <!-- Product dependencies netstandard -->
@@ -50,7 +50,7 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageVersion>
     <PackageVersion Include="GitHubActionsTestLogger" Version="2.4.1" />
-    <PackageVersion Include="Microsoft.Extensions.AI.OpenAI" Version="9.5.0-preview.1.25265.7" />
+    <PackageVersion Include="Microsoft.Extensions.AI.OpenAI" Version="9.6.0-preview.1.25310.2" />
     <PackageVersion Include="Microsoft.Extensions.DependencyInjection" Version="$(System9Version)" />
     <PackageVersion Include="Microsoft.Extensions.Hosting" Version="$(System9Version)" />
     <PackageVersion Include="Microsoft.Extensions.Logging" Version="$(System9Version)" />

src/ModelContextProtocol.Core/McpJsonUtilities.cs

@@ -85,30 +85,6 @@ public static partial class McpJsonUtilities
         return false; // No type keyword found.
     }
 
-    internal static JsonElement? GetReturnSchema(this AIFunction function, AIJsonSchemaCreateOptions? schemaCreateOptions)
-    {
-        // TODO replace with https://github.com/dotnet/extensions/pull/6447 once merged.
-        if (function.UnderlyingMethod?.ReturnType is not Type returnType)
-        {
-            return null;
-        }
-
-        if (returnType == typeof(void) || returnType == typeof(Task) || returnType == typeof(ValueTask))
-        {
-            // Do not report an output schema for void or Task methods.
-            return null;
-        }
-
-        if (returnType.IsGenericType && returnType.GetGenericTypeDefinition() is Type genericTypeDef &&
-            (genericTypeDef == typeof(Task<>) || genericTypeDef == typeof(ValueTask<>)))
-        {
-            // Extract the real type from Task<T> or ValueTask<T> if applicable.
-            returnType = returnType.GetGenericArguments()[0];
-        }
-
-        return AIJsonUtilities.CreateJsonSchema(returnType, serializerOptions: function.JsonSerializerOptions, inferenceOptions: schemaCreateOptions);
-    }
-
     // Keep in sync with CreateDefaultOptions above.
     [JsonSourceGenerationOptions(JsonSerializerDefaults.Web,
         DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
@@ -157,6 +133,7 @@ public static partial class McpJsonUtilities
     [JsonSerializable(typeof(SubscribeRequestParams))]
     [JsonSerializable(typeof(UnsubscribeRequestParams))]
     [JsonSerializable(typeof(IReadOnlyDictionary<string, object>))]
+    [JsonSerializable(typeof(PromptMessage[]))]
 
     // Primitive types for use in consuming AIFunctions
     [JsonSerializable(typeof(string))]

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerPrompt.cs

@@ -71,6 +71,7 @@ internal sealed class AIFunctionMcpServerPrompt : McpServerPrompt
             Description = options?.Description,
             MarshalResult = static (result, _, cancellationToken) => new ValueTask<object?>(result),
             SerializerOptions = options?.SerializerOptions ?? McpJsonUtilities.DefaultOptions,
+            JsonSchemaCreateOptions = options?.SchemaCreateOptions,
             ConfigureParameterBinding = pi =>
             {
                 if (pi.ParameterType == typeof(RequestContext<GetPromptRequestParams>))
@@ -151,7 +152,6 @@ internal sealed class AIFunctionMcpServerPrompt : McpServerPrompt
                     return null;
                 }
             },
-            JsonSchemaCreateOptions = options?.SchemaCreateOptions,
         };
 
     /// <summary>Creates an <see cref="McpServerPrompt"/> that wraps the specified <see cref="AIFunction"/>.</summary>

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerResource.cs

@@ -77,7 +77,8 @@ internal sealed class AIFunctionMcpServerResource : McpServerResource
             Name = options?.Name ?? method.GetCustomAttribute<McpServerResourceAttribute>()?.Name,
             Description = options?.Description,
             MarshalResult = static (result, _, cancellationToken) => new ValueTask<object?>(result),
-            SerializerOptions = McpJsonUtilities.DefaultOptions,
+            SerializerOptions = options?.SerializerOptions ?? McpJsonUtilities.DefaultOptions,
+            JsonSchemaCreateOptions = options?.SchemaCreateOptions,
             ConfigureParameterBinding = pi =>
             {
                 if (pi.ParameterType == typeof(RequestContext<ReadResourceRequestParams>))

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerTool.cs

@@ -86,6 +86,7 @@ internal sealed partial class AIFunctionMcpServerTool : McpServerTool
             Description = options?.Description,
             MarshalResult = static (result, _, cancellationToken) => new ValueTask<object?>(result),
             SerializerOptions = options?.SerializerOptions ?? McpJsonUtilities.DefaultOptions,
+            JsonSchemaCreateOptions = options?.SchemaCreateOptions,
             ConfigureParameterBinding = pi =>
             {
                 if (pi.ParameterType == typeof(RequestContext<CallToolRequestParams>))
@@ -166,7 +167,6 @@ internal sealed partial class AIFunctionMcpServerTool : McpServerTool
                     return null;
                 }
             },
-            JsonSchemaCreateOptions = options?.SchemaCreateOptions,
         };
 
     /// <summary>Creates an <see cref="McpServerTool"/> that wraps the specified <see cref="AIFunction"/>.</summary>
@@ -366,7 +366,7 @@ internal sealed partial class AIFunctionMcpServerTool : McpServerTool
             return null;
         }
 
-        if (function.GetReturnSchema(toolCreateOptions?.SchemaCreateOptions) is not JsonElement outputSchema)
+        if (function.ReturnJsonSchema is not JsonElement outputSchema)
         {
             return null;
         }

src/ModelContextProtocol.Core/Server/McpServerResourceCreateOptions.cs

@@ -1,4 +1,6 @@
+using Microsoft.Extensions.AI;
 using System.ComponentModel;
+using System.Text.Json;
 
 namespace ModelContextProtocol.Server;
 
@@ -60,6 +62,22 @@ public sealed class McpServerResourceCreateOptions
     /// </summary>
     public string? MimeType { get; set; }
 
+    /// <summary>
+    /// Gets or sets the JSON serializer options to use when marshalling data to/from JSON.
+    /// </summary>
+    /// <remarks>
+    /// Defaults to <see cref="McpJsonUtilities.DefaultOptions"/> if left unspecified.
+    /// </remarks>
+    public JsonSerializerOptions? SerializerOptions { get; set; }
+
+    /// <summary>
+    /// Gets or sets the JSON schema options when creating <see cref="AIFunction"/> from a method.
+    /// </summary>
+    /// <remarks>
+    /// Defaults to <see cref="AIJsonSchemaCreateOptions.Default"/> if left unspecified.
+    /// </remarks>
+    public AIJsonSchemaCreateOptions? SchemaCreateOptions { get; set; }
+
     /// <summary>
     /// Creates a shallow clone of the current <see cref="McpServerResourceCreateOptions"/> instance.
     /// </summary>
@@ -71,5 +89,7 @@ public sealed class McpServerResourceCreateOptions
             Name = Name,
             Description = Description,
             MimeType = MimeType,
+            SerializerOptions = SerializerOptions,
+            SchemaCreateOptions = SchemaCreateOptions,
         };
 }

tests/ModelContextProtocol.Tests/Server/McpServerPromptTests.cs

@@ -5,6 +5,8 @@ using ModelContextProtocol.Server;
 using Moq;
 using System.ComponentModel;
 using System.Reflection;
+using System.Text.Json;
+using System.Text.Json.Nodes;
 
 namespace ModelContextProtocol.Tests.Server;
 
@@ -324,6 +326,11 @@ public class McpServerPromptTests
         {
             TransformSchemaNode = (context, node) =>
             {
+                if (node.GetValueKind() is not JsonValueKind.Object)
+                {
+                    node = new JsonObject();
+                }
+
                 node["description"] = "1234";
                 return node;
             }

tests/ModelContextProtocol.Tests/Server/McpServerResourceTests.cs

@@ -451,7 +451,7 @@ public partial class McpServerResourceTests
         {
             Assert.Same(mockServer.Object, server);
             return new TextResourceContents() { Text = "hello" };
-        }, new() { Name = "Test" });
+        }, new() { Name = "Test", SerializerOptions = JsonContext6.Default.Options });
         var result = await resource.ReadAsync(
             new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
             TestContext.Current.CancellationToken);
@@ -507,7 +507,7 @@ public partial class McpServerResourceTests
         {
             Assert.Same(mockServer.Object, server);
             return new List<string>() { "42", "43" };
-        }, new() { Name = "Test" });
+        }, new() { Name = "Test", SerializerOptions = JsonContext6.Default.Options });
         var result = await resource.ReadAsync(
             new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
             TestContext.Current.CancellationToken);
@@ -547,7 +547,7 @@ public partial class McpServerResourceTests
                 new TextContent("hello!"),
                 new DataContent(new byte[] { 4, 5, 6 }, "application/json"),
             };
-        }, new() { Name = "Test" });
+        }, new() { Name = "Test", SerializerOptions = JsonContext6.Default.Options });
         var result = await resource.ReadAsync(
             new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
             TestContext.Current.CancellationToken);
@@ -575,5 +575,8 @@ public partial class McpServerResourceTests
 
     [JsonSourceGenerationOptions(PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase)]
     [JsonSerializable(typeof(DisposableResourceType))]
+    [JsonSerializable(typeof(List<AIContent>))]
+    [JsonSerializable(typeof(List<string>))]
+    [JsonSerializable(typeof(TextResourceContents))]
     partial class JsonContext6 : JsonSerializerContext;
 }

tests/ModelContextProtocol.Tests/Server/McpServerToolTests.cs

@@ -190,7 +190,7 @@ public partial class McpServerToolTests
                 new DataContent("data:image/png;base64,1234"),
                 new DataContent("data:audio/wav;base64,1234")
             };
-        });
+        }, new() { SerializerOptions = JsonContext2.Default.Options });
 
         var result = await tool.InvokeAsync(
             new RequestContext<CallToolRequestParams>(mockServer.Object),
@@ -288,7 +288,7 @@ public partial class McpServerToolTests
         {
             Assert.Same(mockServer.Object, server);
             return new List<string>() { "42", "43" };
-        });
+        }, new() { SerializerOptions = JsonContext2.Default.Options });
         var result = await tool.InvokeAsync(
             new RequestContext<CallToolRequestParams>(mockServer.Object),
             TestContext.Current.CancellationToken);
@@ -632,5 +632,7 @@ public partial class McpServerToolTests
     [JsonSerializable(typeof(AsyncDisposableToolType))]
     [JsonSerializable(typeof(AsyncDisposableAndDisposableToolType))]
     [JsonSerializable(typeof(JsonSchema))]
+    [JsonSerializable(typeof(List<AIContent>))]
+    [JsonSerializable(typeof(List<string>))]
     partial class JsonContext2 : JsonSerializerContext;
 }