Recreate single named schema handling across Map methods

src/HotChocolate/Adapters/src/Adapters.Mcp.Core/Extensions/EndpointRouteBuilderExtensions.cs

@@ -1,5 +1,6 @@
 using System.Diagnostics.CodeAnalysis;
 using HotChocolate.Adapters.Mcp.Proxies;
+using HotChocolate.Execution;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Metadata;
@@ -16,6 +17,7 @@ public static IEndpointConventionBuilder MapGraphQLMcp(
         [StringSyntax("Route")] string pattern = "/graphql/mcp",
         string? schemaName = null)
     {
+        TryResolveSchemaName(endpoints.ServiceProvider, ref schemaName);
         schemaName ??= ISchemaDefinition.DefaultName;
 
         var streamableHttpHandler =
@@ -64,4 +66,14 @@ public static IEndpointConventionBuilder MapGraphQLMcp(
 
         return mcpGroup;
     }
+
+    private static void TryResolveSchemaName(IServiceProvider services, ref string? schemaName)
+    {
+        if (schemaName is null
+            && services.GetService<IRequestExecutorProvider>() is { } provider
+            && provider.SchemaNames.Length == 1)
+        {
+            schemaName = provider.SchemaNames[0];
+        }
+    }
 }

src/HotChocolate/Adapters/src/Adapters.OpenApi.AspNetCore/Extensions/EndpointRouteBuilderExtensions.cs

@@ -1,3 +1,4 @@
+using HotChocolate.Execution;
 using Microsoft.AspNetCore.Routing;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -9,6 +10,7 @@ public static IEndpointRouteBuilder MapOpenApiEndpoints(
         this IEndpointRouteBuilder endpoints,
         string? schemaName = null)
     {
+        TryResolveSchemaName(endpoints.ServiceProvider, ref schemaName);
         schemaName ??= ISchemaDefinition.DefaultName;
 
         var dataSource = endpoints.ServiceProvider.GetRequiredKeyedService<DynamicEndpointDataSource>(schemaName);
@@ -20,4 +22,14 @@ public static IEndpointRouteBuilder MapOpenApiEndpoints(
 
         return endpoints;
     }
+
+    private static void TryResolveSchemaName(IServiceProvider services, ref string? schemaName)
+    {
+        if (schemaName is null
+            && services.GetService<IRequestExecutorProvider>() is { } provider
+            && provider.SchemaNames.Length == 1)
+        {
+            schemaName = provider.SchemaNames[0];
+        }
+    }
 }

src/HotChocolate/Adapters/src/Adapters.OpenApi.AspNetCore/Extensions/OpenApiOptionsExtensions.cs

@@ -1,3 +1,4 @@
+using HotChocolate.Execution;
 using Microsoft.AspNetCore.OpenApi;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -7,14 +8,26 @@ public static class OpenApiOptionsExtensions
 {
     public static OpenApiOptions AddGraphQLTransformer(this OpenApiOptions options, string? schemaName = null)
     {
-        schemaName ??= ISchemaDefinition.DefaultName;
-
         return options.AddDocumentTransformer((document, context, ct) =>
         {
+            var resolvedSchemaName = schemaName;
+            TryResolveSchemaName(context.ApplicationServices, ref resolvedSchemaName);
+            resolvedSchemaName ??= ISchemaDefinition.DefaultName;
+
             var transformer = context.ApplicationServices
-                .GetRequiredKeyedService<DynamicOpenApiDocumentTransformer>(schemaName);
+                .GetRequiredKeyedService<DynamicOpenApiDocumentTransformer>(resolvedSchemaName);
 
             return transformer.TransformAsync(document, context, ct);
         });
     }
+
+    private static void TryResolveSchemaName(IServiceProvider services, ref string? schemaName)
+    {
+        if (schemaName is null
+            && services.GetService<IRequestExecutorProvider>() is { } provider
+            && provider.SchemaNames.Length == 1)
+        {
+            schemaName = provider.SchemaNames[0];
+        }
+    }
 }

src/HotChocolate/Adapters/test/Adapters.Mcp.Tests/CoreIntegrationTests.cs

@@ -20,6 +20,42 @@
 
 public sealed class CoreIntegrationTests : IntegrationTestBase
 {
+    [Fact]
+    public async Task MapGraphQLMcp_Should_ResolveSchemaName_When_SingleNamedSchemaRegistered()
+    {
+        // arrange
+        var storage = new TestMcpStorage();
+        await storage.AddOrUpdateToolAsync(
+            new OperationToolDefinition(
+                Utf8GraphQLParser.Parse("query GetBooks { books { title } }")));
+        var builder = new WebHostBuilder()
+            .ConfigureServices(
+                services => services
+                    .AddRouting()
+                    .AddGraphQL("NamedSchema")
+                    .AddAuthorization()
+                    .AddQueryType<TestSchema.Query>()
+                    .AddMutationType<TestSchema.Mutation>()
+                    .AddInterfaceType<TestSchema.IPet>()
+                    .AddUnionType<TestSchema.IPet>()
+                    .AddObjectType<TestSchema.Cat>()
+                    .AddObjectType<TestSchema.Dog>()
+                    .AddMcp()
+                    .AddMcpStorage(storage))
+            .Configure(
+                app => app
+                    .UseRouting()
+                    .UseEndpoints(endpoints => endpoints.MapGraphQLMcp()));
+        var server = new TestServer(builder);
+        var mcpClient = await CreateMcpClientAsync(server.CreateClient());
+
+        // act
+        var tools = await mcpClient.ListToolsAsync();
+
+        // assert
+        Assert.Equal("get_books", Assert.Single(tools).Name);
+    }
+
     [Fact]
     public async Task ListTools_AfterSchemaUpdate_ReturnsUpdatedTools()
     {
@@ -30,7 +66,7 @@
                 Utf8GraphQLParser.Parse(
                     await File.ReadAllTextAsync("__resources__/GetSingleField.graphql"))));
         var typeModule = new TestTypeModule();
         var builder = new WebHostBuilder()
             .ConfigureServices(
                 services => services
                     .AddRouting()
@@ -42,7 +78,7 @@
                 app => app
                     .UseRouting()
                     .UseEndpoints(endpoints => endpoints.MapGraphQLMcp()));
         var server = new TestServer(builder);
         var mcpClient1 = await CreateMcpClientAsync(server.CreateClient());
         var mcpClient2 = await CreateMcpClientAsync(server.CreateClient());
         var listChangedResetEvent1 = new ManualResetEventSlim(false);
@@ -101,7 +137,7 @@
         Action<McpServerOptions>? configureMcpServerOptions = null,
         Action<IMcpServerBuilder>? configureMcpServer = null)
     {
         var builder = new WebHostBuilder()
             .ConfigureServices(
                 services =>
                 {
@@ -147,7 +183,7 @@
                     .UseAuthentication()
                     .UseEndpoints(endpoints => endpoints.MapGraphQLMcp()));
 
         return Task.FromResult(new TestServer(builder));
     }
 
     private sealed class TestTypeModule : TypeModule

src/HotChocolate/Adapters/test/Adapters.OpenApi.Tests/Endpoints/HttpEndpointIntegrationTests.cs

@@ -1,4 +1,8 @@
+using System.Net;
 using System.Text;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.TestHost;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace HotChocolate.Adapters.OpenApi;
@@ -20,6 +24,41 @@
         }
     }
 
+    [Fact]
+    public async Task MapOpenApiEndpoints_Should_ResolveSchemaName_When_SingleNamedSchemaRegistered()
+    {
+        // arrange
+        var storage = new TestOpenApiDefinitionStorage(
+            """
+            query GetUsers @http(method: GET, route: "/users") {
+              usersWithoutAuth {
+                id
+              }
+            }
+            """);
+        var builder = new WebHostBuilder()
+            .ConfigureServices(services =>
+            {
+                services.AddRouting();
+                services.AddGraphQLServer("NamedSchema")
+                    .AddOpenApiDefinitionStorage(storage)
+                    .AddBasicServer();
+            })
+            .Configure(app =>
+            {
+                app.UseRouting();
+                app.UseEndpoints(endpoints => endpoints.MapOpenApiEndpoints());
+            });
+        var server = new TestServer(builder);
+        var client = server.CreateClient();
+
+        // act
+        var response = await client.GetAsync("/users");
+
+        // assert
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+    }
+
     [Fact]
     public async Task Http_Post_Body_Field_Has_Wrong_Type()
     {

src/HotChocolate/Adapters/test/Adapters.OpenApi.Tests/OpenApi/OpenApiIntegrationTests.cs

@@ -1,3 +1,6 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.TestHost;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace HotChocolate.Adapters.OpenApi;
@@ -13,4 +16,40 @@
             .AddOpenApiDefinitionStorage(storage)
             .AddBasicServer();
     }
+
+    [Fact]
+    public async Task AddGraphQLTransformer_Should_ResolveSchemaName_When_SingleNamedSchemaRegistered()
+    {
+        // arrange
+        var storage = new TestOpenApiDefinitionStorage(
+            """
+            query GetUsers @http(method: GET, route: "/users") {
+              usersWithoutAuth {
+                id
+              }
+            }
+            """);
+        var builder = new WebHostBuilder()
+            .ConfigureServices(services =>
+            {
+                services.AddRouting();
+                services.AddGraphQLServer("NamedSchema")
+                    .AddOpenApiDefinitionStorage(storage)
+                    .AddBasicServer();
+                services.AddOpenApi(options => options.AddGraphQLTransformer());
+            })
+            .Configure(app =>
+            {
+                app.UseRouting();
+                app.UseEndpoints(endpoints => endpoints.MapOpenApi());
+            });
+        using var server = new TestServer(builder);
+        var client = server.CreateClient();
+
+        // act
+        var document = await GetOpenApiDocumentAsync(client);
+
+        // assert
+        Assert.Contains("/users", document);
+    }
 }