From b68722b917e1b221eaaabaa50065870b21e50a83 Mon Sep 17 00:00:00 2001
From: Jihaochang1 <358550956@qq.com>
Date: Fri, 23 Oct 2026 15:21:12 +0800
Subject: [PATCH 1/2] fix: handle HEAD on SSE endpoint to prevent connection
 leaks (fixes #3736)

---
 src/mcp/server/sse.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/mcp/server/sse.py b/src/mcp/server/sse.py
index d71ef25004..ca65e93254 100644
--- a/src/mcp/server/sse.py
+++ b/src/mcp/server/sse.py
@@ -15,6 +15,8 @@
 
     # Define handler functions
     async def handle_sse(request):
+    if scope["method"] == "HEAD":
+        return Response(media_type="text/event-stream", headers={"Cache-Control": "no-store"})
         async with sse.connect_sse(
             request.scope, request.receive, request._send
         ) as streams:

From a466c65e4bc470a80c70a7d363cbccf84d4313e8 Mon Sep 17 00:00:00 2001
From: Jihaochang1 <358550956@qq.com>
Date: Fri, 23 Oct 2026 18:29:15 +0800
Subject: [PATCH 2/2] fix: use get_origin() for typing.GenericAlias detection

Fixes #3745 by checking the origin of type expressions instead of
their class type. typing.Dict[str, Any] is a typing._GenericAlias,
not a types.GenericAlias, so the previous check failed to match it.

This ensures consistent behavior between typing.Dict and dict annotations,
preventing silent schema changes when Ruff UP006 rewrites old-style
annotations to modern syntax.
---
 src/mcp/server/mcpserver/utilities/func_metadata.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mcp/server/mcpserver/utilities/func_metadata.py b/src/mcp/server/mcpserver/utilities/func_metadata.py
index 96d25ec5ab..f8dcd70412 100644
--- a/src/mcp/server/mcpserver/utilities/func_metadata.py
+++ b/src/mcp/server/mcpserver/utilities/func_metadata.py
@@ -500,7 +500,7 @@ def _create_output_model(original_annotation: Any, type_expr: Any, func_name: st
         wrap_output = True
 
     # Handle GenericAlias types (list[str], dict[str, int], Union[str, int], etc.)
-    elif isinstance(type_expr, GenericAlias):
+    elif get_origin(type_expr) is not None:
         origin = get_origin(type_expr)
 
         if origin is dict: