diff --git a/src/Runner.php b/src/Runner.php
index afb704d..0a998e0 100644
--- a/src/Runner.php
+++ b/src/Runner.php
@@ -34,7 +34,7 @@ public function run(): int
 
         $handler = function () use ($server, &$sfRequest, &$sfResponse, $xdebugConnectToClient): void {
             // Connect to the Xdebug client if it's available
-            if ($xdebugConnectToClient) {
+            if ($xdebugConnectToClient && isset($_COOKIE['XDEBUG_SESSION'])) {
                 xdebug_connect_to_client();
             }