diff --git a/api/core/app/apps/advanced_chat/generate_task_pipeline.py b/api/core/app/apps/advanced_chat/generate_task_pipeline.py
index 0076db6165..09371b5c04 100644
--- a/api/core/app/apps/advanced_chat/generate_task_pipeline.py
+++ b/api/core/app/apps/advanced_chat/generate_task_pipeline.py
@@ -3,7 +3,7 @@ import time
 from collections.abc import Callable, Generator, Mapping
 from contextlib import contextmanager
 from threading import Thread
-from typing import Any, Optional, Protocol, Union
+from typing import Any, Optional, Union
 
 from sqlalchemy import select
 from sqlalchemy.orm import Session
@@ -277,18 +277,6 @@ class AdvancedChatAppGenerateTaskPipeline:
         if tts_publisher:
             yield MessageAudioEndStreamResponse(audio="", task_id=task_id)
 
-    class EventHandler(Protocol):
-        """Protocol for event handlers."""
-
-        def __call__(
-            self,
-            event: Any,
-            *,
-            graph_runtime_state: Optional[Any] = None,
-            tts_publisher: Optional[Any] = None,
-            trace_manager: Optional[Any] = None,
-        ) -> Generator[Any, None, None]: ...
-
     @contextmanager
     def _database_session(self):
         """Context manager for database sessions."""
diff --git a/api/core/app/apps/workflow/generate_task_pipeline.py b/api/core/app/apps/workflow/generate_task_pipeline.py
index d262ef4d17..1f38410553 100644
--- a/api/core/app/apps/workflow/generate_task_pipeline.py
+++ b/api/core/app/apps/workflow/generate_task_pipeline.py
@@ -2,7 +2,7 @@ import logging
 import time
 from collections.abc import Callable, Generator
 from contextlib import contextmanager
-from typing import Any, Optional, Protocol, Union
+from typing import Any, Optional, Union
 
 from sqlalchemy.orm import Session
 
@@ -247,19 +247,6 @@ class WorkflowAppGenerateTaskPipeline:
         if tts_publisher:
             yield MessageAudioEndStreamResponse(audio="", task_id=task_id)
 
-    class EventHandler(Protocol):
-        """Protocol for event handlers."""
-
-        def __call__(
-            self,
-            event: Any,
-            *,
-            graph_runtime_state: Optional[Any] = None,
-            tts_publisher: Optional[Any] = None,
-            trace_manager: Optional[Any] = None,
-            queue_message: Optional[Any] = None,
-        ) -> Generator[Any, None, None]: ...
-
     @contextmanager
     def _database_session(self):
         """Context manager for database sessions."""