From 222742a737792319e95cf5d8892e24855bae6f97 Mon Sep 17 00:00:00 2001
From: Perseus Computing <51974392+tcconnally@users.noreply.github.com>
Date: Wed, 24 Jun 2026 10:53:22 -0500
Subject: [PATCH] fix: StatefulProxyClient.clear() no longer causes KeyError on
 session teardown (#4328)

---
 fastmcp_slim/fastmcp/server/providers/proxy.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fastmcp_slim/fastmcp/server/providers/proxy.py b/fastmcp_slim/fastmcp/server/providers/proxy.py
index 8dab75564..f5f160194 100644
--- a/fastmcp_slim/fastmcp/server/providers/proxy.py
+++ b/fastmcp_slim/fastmcp/server/providers/proxy.py
@@ -1230,7 +1230,7 @@ class StatefulProxyClient(ProxyClient[ClientTransportT]):
             self._caches[session] = proxy_client
 
             async def _on_session_exit():
-                self._caches.pop(session)
+                self._caches.pop(session, None)
                 logger.debug(f"{proxy_client} will be disconnect")
                 # This callback runs while the server session's exit stack is
                 # unwinding, which usually happens because the owning task is