diff --git a/core/Microsoft.Mcp.Core/src/Services/Azure/Authentication/WindowHandleProvider.cs b/core/Microsoft.Mcp.Core/src/Services/Azure/Authentication/WindowHandleProvider.cs
index 4eb3483d27..c0abac68d0 100644
--- a/core/Microsoft.Mcp.Core/src/Services/Azure/Authentication/WindowHandleProvider.cs
+++ b/core/Microsoft.Mcp.Core/src/Services/Azure/Authentication/WindowHandleProvider.cs
@@ -26,18 +26,19 @@ public static IntPtr GetWindowHandle()
             try
             {
                 IntPtr display = XOpenDisplay(":1");
-                Console.WriteLine(display == IntPtr.Zero
+
+                // Do not write to standard output because it is interpreted as a JSON RPC response
+                // from the MCP server. Instead, write to standard error for diagnostics.
+                Console.Error.WriteLine(display == IntPtr.Zero
                     ? "No X display available. Running in headless mode."
                     : "X display is available.");
                 return display;
             }
-            catch (Exception)
+            catch (Exception exception)
             {
                 // X11 display detection failed; running in headless mode.
                 // Avoid logging exception details to console to prevent information disclosure.
-                Console.ForegroundColor = ConsoleColor.Red;
-                Console.WriteLine($"Failed to detect X display. Running in headless mode. Exception type: {typeof(Exception).FullName}");
-                Console.ResetColor();
+                Console.Error.WriteLine($"Failed to detect X display. Running in headless mode. Exception type: {exception.GetType().FullName}");
             }
         }
 
diff --git a/servers/Azure.Mcp.Server/changelog-entries/1777662676190.yaml b/servers/Azure.Mcp.Server/changelog-entries/1777662676190.yaml
new file mode 100644
index 0000000000..527c544203
--- /dev/null
+++ b/servers/Azure.Mcp.Server/changelog-entries/1777662676190.yaml
@@ -0,0 +1,3 @@
+changes:
+  - section: "Bugs Fixed"
+    description: "Fix issue where writing exception to stdout is interpreted as JSON RPC response."