Loading the config file to MCP inspector so you can inspect right away (#816)

Author: aaronpowell

examples/mcp-inspector/CommunityToolkit.Aspire.Hosting.McpInspector.McpServer/Program.cs

@@ -10,7 +10,7 @@
 
 var app = builder.Build();
 
-app.MapMcp();
+app.MapMcp("/mcp");
 
 app.Run();
 

src/CommunityToolkit.Aspire.Hosting.McpInspector/McpInspectorResource.cs

@@ -37,7 +37,7 @@ public class McpInspectorResource(string name) : ExecutableResource(name, "npx",
     /// <summary>
     /// Gets the version of the MCP Inspector.
     /// </summary>
-    public const string InspectorVersion = "0.16.2";
+    public const string InspectorVersion = "0.16.5";
 
     private readonly List<McpServerMetadata> _mcpServers = [];
 
@@ -58,7 +58,7 @@ public class McpInspectorResource(string name) : ExecutableResource(name, "npx",
     /// </summary>
     public ParameterResource ProxyTokenParameter { get; set; } = default!;
 
-    internal void AddMcpServer(IResourceWithEndpoints mcpServer, bool isDefault, McpTransportType transportType)
+    internal void AddMcpServer(IResourceWithEndpoints mcpServer, bool isDefault, McpTransportType transportType, string path)
     {
         if (_mcpServers.Any(s => s.Name == mcpServer.Name))
         {
@@ -68,7 +68,8 @@ internal void AddMcpServer(IResourceWithEndpoints mcpServer, bool isDefault, Mcp
         McpServerMetadata item = new(
             mcpServer.Name,
             mcpServer.GetEndpoint("http") ?? throw new InvalidOperationException($"The MCP server {mcpServer.Name} must have a 'http' endpoint defined."),
-            transportType);
+            transportType,
+            path);
 
         _mcpServers.Add(item);
 

src/CommunityToolkit.Aspire.Hosting.McpInspector/McpInspectorResourceBuilderExtensions.cs

@@ -70,15 +70,15 @@ public static IResourceBuilder<McpInspectorResource> AddMcpInspector(this IDistr
 
                 var servers = inspectorResource.McpServers.ToDictionary(s => s.Name, s => new
                 {
-                    transport = s.TransportType switch
+                    type = s.TransportType switch
                     {
                         McpTransportType.StreamableHttp => "streamable-http",
 #pragma warning disable CS0618
                         McpTransportType.Sse => "sse",
 #pragma warning restore CS0618
                         _ => throw new NotSupportedException($"The transport type {s.TransportType} is not supported.")
                     },
-                    endpoint = s.Endpoint.Url
+                    url = Combine(s.Endpoint.Url, s.Path),
                 });
 
                 var config = new { mcpServers = servers };
@@ -183,18 +183,20 @@ public static IResourceBuilder<McpInspectorResource> AddMcpInspector(this IDistr
     /// <param name="mcpServer">The <see cref="IResourceBuilder{T}"/> for the MCP server resource.</param>
     /// <param name="isDefault">Indicates whether this MCP server should be considered the default server for the MCP Inspector.</param>
     /// <param name="transportType">The transport type to use for the MCP server. Defaults to <see cref="McpTransportType.StreamableHttp"/>.</param>
+    /// <param name="path">The path to use for MCP communication. Defaults to "/mcp".</param>
     /// <returns>A reference to the <see cref="IResourceBuilder{McpInspectorResource}"/> for further configuration.</returns>
     public static IResourceBuilder<McpInspectorResource> WithMcpServer<TResource>(
         this IResourceBuilder<McpInspectorResource> builder,
         IResourceBuilder<TResource> mcpServer,
         bool isDefault = true,
-        McpTransportType transportType = McpTransportType.StreamableHttp)
+        McpTransportType transportType = McpTransportType.StreamableHttp,
+        string path = "/mcp")
         where TResource : IResourceWithEndpoints
     {
         ArgumentNullException.ThrowIfNull(mcpServer);
         ArgumentNullException.ThrowIfNull(builder);
 
-        builder.Resource.AddMcpServer(mcpServer.Resource, isDefault, transportType);
+        builder.Resource.AddMcpServer(mcpServer.Resource, isDefault, transportType, path);
         return builder;
     }
 
@@ -222,4 +224,27 @@ private static IResourceBuilder<McpInspectorResource> WithDefaultArgs(this IReso
                 ctx.Args.Add(defaultMcpServer?.Name ?? throw new InvalidOperationException("The MCP Inspector resource must have a default MCP server defined."));
             });
     }
+
+    internal static Uri Combine(string baseUrl, params string[] segments)
+    {
+        if (string.IsNullOrEmpty(baseUrl))
+            throw new ArgumentException("baseUrl required", nameof(baseUrl));
+
+        if (segments == null || segments.Length == 0)
+            return new Uri(baseUrl, UriKind.RelativeOrAbsolute);
+
+        var baseUri = new Uri(baseUrl, UriKind.Absolute);
+
+        // If first segment is absolute URI, return it
+        if (Uri.IsWellFormedUriString(segments[0], UriKind.Absolute))
+            return new Uri(segments[0], UriKind.Absolute);
+
+        var escaped = segments
+            .Where(s => !string.IsNullOrEmpty(s))
+            .Select(s => Uri.EscapeDataString(s.Trim('/')));
+
+        var relative = string.Join("/", escaped);
+
+        return new Uri(baseUri, relative);
+    }
 }

src/CommunityToolkit.Aspire.Hosting.McpInspector/McpServerMetadata.cs

@@ -6,4 +6,5 @@ namespace Aspire.Hosting.ApplicationModel;
 /// <param name="Name">The name of the server resource.</param>
 /// <param name="Endpoint">The endpoint reference for the server resource.</param>
 /// <param name="TransportType">The transport type used by the server resource.</param>
-public record McpServerMetadata(string Name, EndpointReference Endpoint, McpTransportType TransportType);
+/// <param name="Path">The path used for MCP communication.</param>
+public record McpServerMetadata(string Name, EndpointReference Endpoint, McpTransportType TransportType, string Path);

tests/CommunityToolkit.Aspire.Hosting.McpInspector.Tests/McpInspectorResourceBuilderExtensionsTests.cs

@@ -63,6 +63,33 @@ public void WithMcpServerSpecificTransportTypeAddsServerToResource(McpTransportT
         Assert.Equal(transportType, inspectorResource.DefaultMcpServer.TransportType);
     }
 
+    [Fact]
+    public void WithMcpServerCustomPathAddsServerWithCustomPath()
+    {
+        // Arrange
+        var appBuilder = DistributedApplication.CreateBuilder();
+
+        // Create a mock MCP server resource
+        var mockServer = appBuilder.AddProject<Projects.CommunityToolkit_Aspire_Hosting_McpInspector_McpServer>("mcpServer");
+
+        // Act
+        var inspector = appBuilder.AddMcpInspector("inspector")
+            .WithMcpServer(mockServer, isDefault: true, path: "/custom/mcp/path");
+
+        using var app = appBuilder.Build();
+
+        // Assert
+        var appModel = app.Services.GetRequiredService<DistributedApplicationModel>();
+
+        var inspectorResource = Assert.Single(appModel.Resources.OfType<McpInspectorResource>());
+        Assert.Equal("inspector", inspectorResource.Name);
+
+        Assert.Single(inspectorResource.McpServers);
+        Assert.NotNull(inspectorResource.DefaultMcpServer);
+        Assert.Equal("mcpServer", inspectorResource.DefaultMcpServer.Name);
+        Assert.Equal("/custom/mcp/path", inspectorResource.DefaultMcpServer.Path);
+    }
+
     [Fact]
     public void WithMultipleMcpServersAddsAllServersToResource()
     {