From 9ba1f47d77a742489f9a3ff8dec72db0ee33b4de Mon Sep 17 00:00:00 2001
From: Kirill Osenkov <KirillOsenkov@users.noreply.github.com>
Date: Mon, 22 Jun 2026 16:52:47 -0700
Subject: [PATCH] Enable netfx UI MCP clients (#1639)

---
 .../Client/StdioClientTransport.cs            | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/ModelContextProtocol.Core/Client/StdioClientTransport.cs b/src/ModelContextProtocol.Core/Client/StdioClientTransport.cs
index b0af062..2e44ee3 100644
--- a/src/ModelContextProtocol.Core/Client/StdioClientTransport.cs
+++ b/src/ModelContextProtocol.Core/Client/StdioClientTransport.cs
@@ -187,14 +187,29 @@ public sealed partial class StdioClientTransport : IClientTransport
             lock (s_consoleEncodingLock)
             {
                 Encoding originalInputEncoding = Console.InputEncoding;
+                bool encodingChanged = false;
                 try
                 {
-                    Console.InputEncoding = StreamClientSessionTransport.NoBomUtf8Encoding;
+                    try
+                    {
+                        Console.InputEncoding = StreamClientSessionTransport.NoBomUtf8Encoding;
+                        encodingChanged = true;
+                    }
+                    catch
+                    {
+                        // Host has no usable console (e.g. WPF/WinForms on .NET Framework with no
+                        // AllocConsole). The child inherits the current Console.InputEncoding;
+                        // non-ASCII stdin may be misencoded, but the connect itself proceeds.
+                    }
+
                     processStarted = process.Start();
                 }
                 finally
                 {
-                    Console.InputEncoding = originalInputEncoding;
+                    if (encodingChanged)
+                    {
+                        Console.InputEncoding = originalInputEncoding;
+                    }
                 }
             }
 #endif