Fix local HTTP server UI check

MCPForUnity/Editor/Services/IServerManagementService.cs

@@ -35,6 +35,12 @@ public interface IServerManagementService
         /// </summary>
         bool IsLocalHttpServerRunning();
 
+        /// <summary>
+        /// Fast reachability check: returns true if a local TCP listener is accepting connections
+        /// for the configured local URL/port (used for UI state without process inspection).
+        /// </summary>
+        bool IsLocalHttpServerReachable();
+
         /// <summary>
         /// Attempts to get the command that will be executed when starting the local HTTP server
         /// </summary>

MCPForUnity/Editor/Services/ServerManagementService.cs

@@ -3,6 +3,7 @@
 using System.Linq;
 using System.Collections.Generic;
 using System.Globalization;
+using System.Net.Sockets;
 using System.Security.Cryptography;
 using System.Text;
 using MCPForUnity.Editor.Constants;
@@ -600,6 +601,75 @@ public bool IsLocalHttpServerRunning()
             }
         }
 
+        public bool IsLocalHttpServerReachable()
+        {
+            try
+            {
+                string httpUrl = HttpEndpointUtility.GetBaseUrl();
+                if (!IsLocalUrl(httpUrl))
+                {
+                    return false;
+                }
+
+                if (!Uri.TryCreate(httpUrl, UriKind.Absolute, out var uri) || uri.Port <= 0)
+                {
+                    return false;
+                }
+
+                return TryConnectToLocalPort(uri.Host, uri.Port, timeoutMs: 50);
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        private static bool TryConnectToLocalPort(string host, int port, int timeoutMs)
+        {
+            try
+            {
+                if (string.IsNullOrEmpty(host))
+                {
+                    host = "127.0.0.1";
+                }
+
+                var hosts = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { host };
+                if (host == "localhost" || host == "0.0.0.0")
+                {
+                    hosts.Add("127.0.0.1");
+                }
+                if (host == "::" || host == "0:0:0:0:0:0:0:0")
+                {
+                    hosts.Add("::1");
+                }
+
+                foreach (var target in hosts)
+                {
+                    try
+                    {
+                        using (var client = new TcpClient())
+                        {
+                            var connectTask = client.ConnectAsync(target, port);
+                            if (connectTask.Wait(timeoutMs) && client.Connected)
+                            {
+                                return true;
+                            }
+                        }
+                    }
+                    catch
+                    {
+                        // Ignore per-host failures.
+                    }
+                }
+            }
+            catch
+            {
+                // Ignore probe failures and treat as unreachable.
+            }
+
+            return false;
+        }
+
         private bool StopLocalHttpServerInternal(bool quiet, int? portOverride = null, bool allowNonLocalUrl = false)
         {
             string httpUrl = HttpEndpointUtility.GetBaseUrl();

MCPForUnity/Editor/Windows/Components/Connection/McpConnectionSection.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Net.Sockets;
 using System.Threading.Tasks;
 using MCPForUnity.Editor.Constants;
 using MCPForUnity.Editor.Helpers;
@@ -482,14 +481,14 @@ private void UpdateStartHttpButtonState()
             bool canStartLocalServer = httpLocalSelected && MCPServiceLocator.Server.IsLocalUrl();
             bool localServerRunning = false;
 
-            // Avoid running expensive port/PID checks every UI tick.
+            // Avoid running expensive port/PID checks every UI tick; use a fast socket probe for UI state.
             if (httpLocalSelected)
             {
                 double now = EditorApplication.timeSinceStartup;
                 if ((now - lastLocalServerRunningPollTime) > 0.75f || httpServerToggleInProgress)
                 {
                     lastLocalServerRunningPollTime = now;
-                    lastLocalServerRunning = MCPServiceLocator.Server.IsLocalHttpServerRunning();
+                    lastLocalServerRunning = MCPServiceLocator.Server.IsLocalHttpServerReachable();
                 }
                 localServerRunning = lastLocalServerRunning;
             }
@@ -531,7 +530,7 @@ private async void OnHttpServerToggleClicked()
             try
             {
                 // Check if a local server is running.
-                bool serverRunning = IsHttpLocalSelected() && MCPServiceLocator.Server.IsLocalHttpServerRunning();
+                bool serverRunning = IsHttpLocalSelected() && MCPServiceLocator.Server.IsLocalHttpServerReachable();
 
                 if (serverRunning)
                 {
@@ -591,7 +590,7 @@ private async Task TryAutoStartSessionAsync()
                 var delay = attempt < 6 ? shortDelay : longDelay;
 
                 // Check if server is actually accepting connections
-                bool serverDetected = MCPServiceLocator.Server.IsLocalHttpServerRunning();
+                bool serverDetected = MCPServiceLocator.Server.IsLocalHttpServerReachable();
 
                 if (serverDetected)
                 {