From 2960ada2b48f135a6265a4d1c613df01908dc9dc Mon Sep 17 00:00:00 2001
From: Mukunda Rao Katta <mukunda.vjcs6@gmail.com>
Date: Sun, 26 Apr 2026 14:26:49 -0700
Subject: [PATCH 1/2] perf(server): skip IdleTrackingBackgroundService timer in
 stateless mode

---
 .../IdleTrackingBackgroundService.cs                  | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/ModelContextProtocol.AspNetCore/IdleTrackingBackgroundService.cs b/src/ModelContextProtocol.AspNetCore/IdleTrackingBackgroundService.cs
index d68f83e5d..645253d6f 100644
--- a/src/ModelContextProtocol.AspNetCore/IdleTrackingBackgroundService.cs
+++ b/src/ModelContextProtocol.AspNetCore/IdleTrackingBackgroundService.cs
@@ -31,6 +31,17 @@ public IdleTrackingBackgroundService(
         _logger = logger;
     }
 
+    public override Task StartAsync(CancellationToken cancellationToken)
+    {
+        // In stateless mode there are no sessions to track, so skip starting the periodic timer entirely.
+        if (_options.Value.Stateless)
+        {
+            return Task.CompletedTask;
+        }
+
+        return base.StartAsync(cancellationToken);
+    }
+
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
         try

From 6fb82b8ceaefa39a6b012b863ee183503e720ec0 Mon Sep 17 00:00:00 2001
From: Mukunda Rao Katta <mukunda.vjcs6@gmail.com>
Date: Sun, 26 Apr 2026 14:27:00 -0700
Subject: [PATCH 2/2] test: assert IdleTrackingBackgroundService timer is gated
 by Stateless option

---
 .../HttpMcpServerBuilderExtensionsTests.cs    | 50 +++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/tests/ModelContextProtocol.AspNetCore.Tests/HttpMcpServerBuilderExtensionsTests.cs b/tests/ModelContextProtocol.AspNetCore.Tests/HttpMcpServerBuilderExtensionsTests.cs
index cc6ff0b13..ef385ed70 100644
--- a/tests/ModelContextProtocol.AspNetCore.Tests/HttpMcpServerBuilderExtensionsTests.cs
+++ b/tests/ModelContextProtocol.AspNetCore.Tests/HttpMcpServerBuilderExtensionsTests.cs
@@ -2,6 +2,7 @@
 using Microsoft.Extensions.Caching.Distributed;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Options;
 using ModelContextProtocol.AspNetCore.Tests.Utils;
 using ModelContextProtocol.Protocol;
@@ -184,6 +185,55 @@ public void SessionMigrationHandler_RemainsNull_WhenNothingIsRegistered()
         Assert.Null(options.SessionMigrationHandler);
     }
 
+    [Fact]
+    public async Task IdleTrackingBackgroundService_DoesNotStartTimer_WhenStateless()
+    {
+        Builder.Services
+            .AddMcpServer()
+            .WithHttpTransport(options => options.Stateless = true);
+
+        using var app = Builder.Build();
+
+        var idleTrackingService = GetIdleTrackingService(app.Services);
+        Assert.NotNull(idleTrackingService);
+
+        await idleTrackingService.StartAsync(TestContext.Current.CancellationToken);
+
+        // BackgroundService.ExecuteTask is only set when ExecuteAsync has been kicked off via base.StartAsync.
+        // In stateless mode we early-return, so ExecuteTask should remain null.
+        Assert.Null(idleTrackingService.ExecuteTask);
+
+        await idleTrackingService.StopAsync(TestContext.Current.CancellationToken);
+    }
+
+    [Fact]
+    public async Task IdleTrackingBackgroundService_StartsTimer_WhenStateful()
+    {
+        Builder.Services
+            .AddMcpServer()
+            .WithHttpTransport();
+
+        using var app = Builder.Build();
+
+        var idleTrackingService = GetIdleTrackingService(app.Services);
+        Assert.NotNull(idleTrackingService);
+
+        await idleTrackingService.StartAsync(TestContext.Current.CancellationToken);
+
+        // In the default (stateful) mode the timer loop must start, so ExecuteTask should be set.
+        Assert.NotNull(idleTrackingService.ExecuteTask);
+
+        await idleTrackingService.StopAsync(TestContext.Current.CancellationToken);
+    }
+
+    private static BackgroundService? GetIdleTrackingService(IServiceProvider services)
+    {
+        // IdleTrackingBackgroundService is internal, so look it up by type name from the registered IHostedService instances.
+        return services.GetServices<IHostedService>()
+            .OfType<BackgroundService>()
+            .FirstOrDefault(s => s.GetType().Name == "IdleTrackingBackgroundService");
+    }
+
     private sealed class StubSessionMigrationHandler : ISessionMigrationHandler
     {
         public ValueTask<InitializeRequestParams?> AllowSessionMigrationAsync(