From 56b165537fa2fb745433f71e5889a46cc2275892 Mon Sep 17 00:00:00 2001
From: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
Date: Fri, 6 Mar 2026 17:31:19 -0500
Subject: [PATCH] =?UTF-8?q?Fix=20initialize=20McpError=20fallthrough=20?=
 =?UTF-8?q?=F0=9F=A4=96=20Generated=20with=20Codex=20(#3413)?=
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---
 src/fastmcp/server/low_level.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/fastmcp/server/low_level.py b/src/fastmcp/server/low_level.py
index 2bc004ff3..420424fc1 100644
--- a/src/fastmcp/server/low_level.py
+++ b/src/fastmcp/server/low_level.py
@@ -144,6 +144,7 @@ class MiddlewareServerSession(ServerSession):
                             "Cannot send error response as response was already sent.",
                             exc_info=e,
                         )
+                    return None
 
         # Fall through to default handling (task methods now handled via registered handlers)
         return await super()._received_request(responder)