Add MCP Apps UI support with SDK dashboard

DotNetMcp.Tests/Server/McpAppsMetaWireFormatTest.cs

@@ -0,0 +1,116 @@
+using System.Runtime.InteropServices;
+using System.Text.Json;
+using ModelContextProtocol.Client;
+using ModelContextProtocol.Protocol;
+using Xunit;
+
+namespace DotNetMcp.Tests;
+
+/// <summary>
+/// Verifies the wire format of _meta.ui on the dotnet_sdk tool,
+/// ensuring both modern nested and legacy flat key formats are present
+/// for MCP Apps compatibility with VS Code.
+/// </summary>
+public class McpAppsMetaWireFormatTest : IAsyncLifetime
+{
+    private McpClient? _client;
+
+    public async ValueTask InitializeAsync()
+    {
+        var serverPath = GetServerExecutablePath();
+        var transportOptions = new StdioClientTransportOptions
+        {
+            Command = serverPath.command,
+            Arguments = serverPath.arguments,
+            Name = "dotnet-mcp-test",
+        };
+
+        _client = await McpClient.CreateAsync(
+            new StdioClientTransport(transportOptions));
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_client != null)
+            await _client.DisposeAsync();
+    }
+
+    [Fact]
+    public async Task DotnetSdk_Meta_Ui_HasModernNestedFormat()
+    {
+        Assert.NotNull(_client);
+
+        var meta = await GetSdkToolMeta();
+
+        Assert.True(meta.TryGetProperty("ui", out var ui), "_meta should contain 'ui' key");
+        Assert.Equal(JsonValueKind.Object, ui.ValueKind);
+        Assert.True(ui.TryGetProperty("resourceUri", out var resourceUri),
+            "_meta.ui should contain 'resourceUri'");
+        Assert.Equal("ui://dotnet-mcp/sdk-dashboard", resourceUri.GetString());
+    }
+
+    [Fact]
+    public async Task DotnetSdk_Meta_Ui_HasLegacyFlatKey()
+    {
+        Assert.NotNull(_client);
+
+        var meta = await GetSdkToolMeta();
+
+        // Legacy flat key required for VS Code compatibility
+        Assert.True(meta.TryGetProperty("ui/resourceUri", out var legacyUri),
+            "_meta should contain legacy 'ui/resourceUri' flat key (required for VS Code)");
+        Assert.Equal("ui://dotnet-mcp/sdk-dashboard", legacyUri.GetString());
+    }
+
+    private async Task<JsonElement> GetSdkToolMeta()
+    {
+        var tools = await _client!.ListToolsAsync(
+            cancellationToken: TestContext.Current.CancellationToken);
+        var sdkTool = tools.FirstOrDefault(t => t.Name == "dotnet_sdk");
+        Assert.NotNull(sdkTool);
+
+        var json = JsonSerializer.Serialize(sdkTool.ProtocolTool);
+        using var doc = JsonDocument.Parse(json);
+        var root = doc.RootElement;
+
+        Assert.True(root.TryGetProperty("_meta", out var meta),
+            "dotnet_sdk tool should have _meta field");
+        return meta.Clone();
+    }
+
+    /// <summary>
+    /// Finds the pre-built DotNetMcp server binary, matching the same
+    /// configuration/framework as the test project to work in CI.
+    /// </summary>
+    private static (string command, string[] arguments) GetServerExecutablePath()
+    {
+        var testBinaryDir = AppContext.BaseDirectory;
+        var configuration = Path.GetFileName(Path.GetDirectoryName(testBinaryDir.TrimEnd(Path.DirectorySeparatorChar))!);
+        var targetFramework = Path.GetFileName(testBinaryDir.TrimEnd(Path.DirectorySeparatorChar));
+
+        var serverBinaryDir = Path.GetFullPath(
+            Path.Join(testBinaryDir, "..", "..", "..", "..", "DotNetMcp", "bin", configuration, targetFramework));
+
+        if (!Directory.Exists(serverBinaryDir))
+        {
+            throw new DirectoryNotFoundException(
+                $"Server binary directory not found at: {serverBinaryDir}. " +
+                $"Make sure DotNetMcp project is built before running tests.");
+        }
+
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        {
+            var exePath = Path.Join(serverBinaryDir, "DotNetMcp.exe");
+            if (!File.Exists(exePath))
+                throw new FileNotFoundException($"Server executable not found at: {exePath}");
+            return (exePath, Array.Empty<string>());
+        }
+        else
+        {
+            var dllPath = Path.Join(serverBinaryDir, "DotNetMcp.dll");
+            if (!File.Exists(dllPath))
+                throw new FileNotFoundException($"Server assembly not found at: {dllPath}");
+            return ("dotnet", new[] { dllPath });
+        }
+    }
+}

DotNetMcp/Program.cs

@@ -73,6 +73,7 @@
     .WithStdioServerTransport()
     .WithTools<DotNetCliTools>()
     .WithResources<DotNetResources>()
+    .WithResources<McpAppsResources>()
     .WithPrompts<DotNetPrompts>()
     .WithSubscribeToResourcesHandler((context, ct) =>
     {