From 44d3f8d858a5960be4998d05b081d237c635613d Mon Sep 17 00:00:00 2001
From: Ashwin Madavan <ashwin.madavan@gmail.com>
Date: Mon, 4 May 2026 11:50:39 -0500
Subject: [PATCH] fix(ping): exit ping loop cleanly when session stream is
 closed (#4087)

---
 src/fastmcp/server/middleware/ping.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/fastmcp/server/middleware/ping.py b/src/fastmcp/server/middleware/ping.py
index a8e35bf2d..0fa3966fb 100644
--- a/src/fastmcp/server/middleware/ping.py
+++ b/src/fastmcp/server/middleware/ping.py
@@ -65,6 +65,9 @@ class PingMiddleware(Middleware):
         try:
             while True:
                 await anyio.sleep(self.interval_ms / 1000)
-                await session.send_ping()
+                try:
+                    await session.send_ping()
+                except anyio.ClosedResourceError:
+                    return
         finally:
             self._active_sessions.discard(session_id)