Graceful shutdown when using custom http.Server

[duaraghav8]

Hi,
I'm currently trying to add SSE session management in my MCP gateway

When I create a new SSEServer for the gateway, I don't use its Start() method to run the server.

Instead, I use my custom http.Server object because I also need to add lots of other http routes to my server for other purposes.

But when I run the Shutdown() method on my SSEServer, it doesn't seem to call the Unregister Session callback from the hooks.
Because of this, I'm unable to perform a graceful shutdown because I need to run cleanups inside the callback.

Minimal code to reproduce this:

package main

import (
	"context"
	"errors"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/mark3labs/mcp-go/server"
)

func main() {
	hooks := &server.Hooks{}

	hooks.AddOnRegisterSession(func(ctx context.Context, sess server.ClientSession) {
		fmt.Println("register called for session:", sess.SessionID())
	})
	hooks.AddOnUnregisterSession(func(ctx context.Context, sess server.ClientSession) {
		fmt.Println("unregister called for session:", sess.SessionID())
	})

	// 1) Core MCP server (name/version are arbitrary)
	s := server.NewMCPServer(
		"mcp-go-sse-demo",
		"0.1.0",
		server.WithHooks(hooks),
	)

	sse := server.NewSSEServer(s)

	httpServer := &http.Server{
		Addr:    "localhost:9000",
		Handler: sse,
	}

	// 4) Graceful shutdown on SIGINT/SIGTERM
	shutdown := make(chan struct{})
	go func() {
		if err := httpServer.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			log.Fatalf("HTTP server failed: %v", err)
		}
		close(shutdown)
	}()

	log.Println("SSE MCP server listening on http://localhost:9000")

	// Wait for signal to close app
	sig := make(chan os.Signal, 1)
	signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
	<-sig

	fmt.Println("got signal, Shutting down...")

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	fmt.Println("shutting down sse server")
	// I expect this Shutdown() to call OnUnregisterSession() for each open connection,
	if err := sse.Shutdown(ctx); err != nil {
		log.Printf("shutdown error: %v", err)
	}

	fmt.Println("shutting down http server")
	// As long as there's even a single open SSE connection, the ctx always times out
	if err := httpServer.Shutdown(ctx); err != nil {
		log.Printf("HTTP server shutdown error: %v", err)
	}

	<-shutdown
	log.Println("Server stopped.")
}

1. Run this app
2. In another terminal, run curl localhost:9000/sse. Keep it open.
3. If you close the curl client connection, you will see the unregister callback being called (log)
4. Now try to close the server with Ctrl+C (or whatever your interrupt keys are). You will NOT see the callback called. I was expecting to see the callback log here as well.

Note that if, instead of using my custom http.Server, I were simply using sse.Start() to run the server, then the callback will be called and graceful shutdown is possible.
So I don't understand what is happening differently due to my custom http.Server.

Can someone please suggest what am I doing wrong and how to do this correctly?

Thanks