diff --git a/backend/open_webui/utils/filter.py b/backend/open_webui/utils/filter.py
index b3ca4a4229..7d8b3e0a78 100644
--- a/backend/open_webui/utils/filter.py
+++ b/backend/open_webui/utils/filter.py
@@ -13,7 +13,6 @@ class FilterContext:
         self.valves_by_id = None
         self.function_valves = {}
         self.user_valves = {}
-        self.signatures = {}
 
     async def get_function_valves(self, filter_ids, filter_id, Valves):
         if filter_id not in self.function_valves:
@@ -23,12 +22,6 @@ class FilterContext:
             self.function_valves[filter_id] = Valves(**(valves if valves else {}))
         return self.function_valves[filter_id]
 
-    def get_signature(self, handler):
-        signature_key = getattr(handler, '__func__', handler)
-        if signature_key not in self.signatures:
-            self.signatures[signature_key] = inspect.signature(handler)
-        return self.signatures[signature_key]
-
     async def get_user_valves(self, filter_id, user_id, UserValves):
         user_valves_key = (filter_id, user_id)
         if user_valves_key not in self.user_valves:
@@ -182,7 +175,7 @@ async def process_filter_function(
     valves_by_id = await apply_filter_valves(function_module, filter_context, valves_by_id, filter_ids, filter_id)
 
     try:
-        sig = filter_context.get_signature(handler) if filter_context is not None else inspect.signature(handler)
+        sig = inspect.signature(handler)
         params = get_filter_params(sig, filter_id, filter_type, form_data, extra_params)
 
         if '__user__' in sig.parameters: