diff --git a/src/mcp/server/session.py b/src/mcp/server/session.py
index 5c696b136a..8e2adc24e0 100644
--- a/src/mcp/server/session.py
+++ b/src/mcp/server/session.py
@@ -93,9 +93,9 @@ def __init__(
         )
 
         self._init_options = init_options
-        self._incoming_message_stream_writer, self._incoming_message_stream_reader = anyio.create_memory_object_stream[
-            ServerRequestResponder
-        ](0)
+        self._incoming_message_stream_writer, self._incoming_message_stream_reader = (
+            anyio.create_memory_object_stream(0)
+        )
         self._exit_stack.push_async_callback(lambda: self._incoming_message_stream_reader.aclose())
 
     @property