MCP Server - Can not figure out what port its opening

[chaoscode]

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Discussion Topic

I'm very new to this but I have a MCP server I built that runs. However, I can not find the port that is opened for the MCP server in the interface, nor do I see a port that gets open when I do netstat. How are we suppose to know what port to configure to connect to the MCP server? Thank you in advanced.

This is my program:

using MCPServer.Tools;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

var builder = Host.CreateApplicationBuilder(args);
builder.Logging.AddConsole(consoleLogOptions =>
{
    // Configure all logs to go to stderr
    consoleLogOptions.LogToStandardErrorThreshold = LogLevel.Trace;
});

// Build Service
builder.Services
    .AddMcpServer()
    .WithStdioServerTransport()
    .WithTools<ToolClass>()
    .WithToolsFromAssembly();

// Build Host
var host = builder.Build();

// Run the server
await host.RunAsync();

[jamp-scp28]

Hey @chaoscode; if you're looking to connect to the server over http, I think you can refer to this example: https://github.com/modelcontextprotocol/csharp-sdk/tree/main/samples/AspNetCoreSseServer.

The WithStdioServerTransport, docs say: This transport launches an external process and communicates with it through standard input and output streams., so I guess you won't find any port related to that process as it's not suppose to.

[chaoscode]

thanks for the comment back. Yeah, I figured that part out. MCP sdk is so new they have not worked most stuff out yet so it needs time to cook more.

[CharlieDigital]

Hmmm...I don't see how this is configured at runtime separate from the launchSettings which have a port.

If I use:

ASPNETCORE_HTTP_PORTS=8081 dotnet run

and then curl this, there is no listener.

It also does not seem to pick up:

{
  "Kestrel": {
    "Endpoints": {
      "McpEndpoint": {
        "Url": "http://localhost:8080"
      }
    }
  }
}

Anyone have this figured out?