diff --git a/api/core/callback_handler/agent_tool_callback_handler.py b/api/core/callback_handler/agent_tool_callback_handler.py
index f31b43cb7f..eb38a5fed0 100644
--- a/api/core/callback_handler/agent_tool_callback_handler.py
+++ b/api/core/callback_handler/agent_tool_callback_handler.py
@@ -103,9 +103,9 @@ class DifyAgentCallbackHandler(BaseModel):
     @property
     def ignore_agent(self) -> bool:
         """Whether to ignore agent callbacks."""
-        return not os.environ.get("DEBUG") or os.environ.get("DEBUG").lower() != "true"
+        return not os.environ.get("DEBUG") or os.environ.get("DEBUG", "").lower() != "true"
 
     @property
     def ignore_chat_model(self) -> bool:
         """Whether to ignore chat model callbacks."""
-        return not os.environ.get("DEBUG") or os.environ.get("DEBUG").lower() != "true"
+        return not os.environ.get("DEBUG") or os.environ.get("DEBUG", "").lower() != "true"
diff --git a/api/core/callback_handler/plugin_tool_callback_handler.py b/api/core/callback_handler/plugin_tool_callback_handler.py
deleted file mode 100644
index 033b8d423c..0000000000
--- a/api/core/callback_handler/plugin_tool_callback_handler.py
+++ /dev/null
@@ -1,5 +0,0 @@
-from core.callback_handler.agent_tool_callback_handler import DifyAgentCallbackHandler
-
-
-class DifyPluginCallbackHandler(DifyAgentCallbackHandler):
-    """Callback Handler that prints to std out."""
diff --git a/api/core/callback_handler/workflow_tool_callback_handler.py b/api/core/callback_handler/workflow_tool_callback_handler.py
index 8ac12f72f2..350b18772b 100644
--- a/api/core/callback_handler/workflow_tool_callback_handler.py
+++ b/api/core/callback_handler/workflow_tool_callback_handler.py
@@ -1,5 +1,26 @@
-from core.callback_handler.agent_tool_callback_handler import DifyAgentCallbackHandler
+from collections.abc import Generator, Iterable, Mapping
+from typing import Any, Optional
+
+from core.callback_handler.agent_tool_callback_handler import DifyAgentCallbackHandler, print_text
+from core.ops.ops_trace_manager import TraceQueueManager
+from core.tools.entities.tool_entities import ToolInvokeMessage
 
 
 class DifyWorkflowCallbackHandler(DifyAgentCallbackHandler):
     """Callback Handler that prints to std out."""
+
+    def on_tool_execution(
+        self,
+        tool_name: str,
+        tool_inputs: Mapping[str, Any],
+        tool_outputs: Iterable[ToolInvokeMessage],
+        message_id: Optional[str] = None,
+        timer: Optional[Any] = None,
+        trace_manager: Optional[TraceQueueManager] = None,
+    ) -> Generator[ToolInvokeMessage, None, None]:
+        for tool_output in tool_outputs:
+            print_text("\n[on_tool_execution]\n", color=self.color)
+            print_text("Tool: " + tool_name + "\n", color=self.color)
+            print_text("Outputs: " + tool_output.model_dump_json()[:1000] + "\n", color=self.color)
+            print_text("\n")
+            yield tool_output
diff --git a/api/core/tools/tool_engine.py b/api/core/tools/tool_engine.py
index d8889917f0..5396acc285 100644
--- a/api/core/tools/tool_engine.py
+++ b/api/core/tools/tool_engine.py
@@ -9,7 +9,6 @@ from yarl import URL
 
 from core.app.entities.app_invoke_entities import InvokeFrom
 from core.callback_handler.agent_tool_callback_handler import DifyAgentCallbackHandler
-from core.callback_handler.plugin_tool_callback_handler import DifyPluginCallbackHandler
 from core.callback_handler.workflow_tool_callback_handler import DifyWorkflowCallbackHandler
 from core.file.file_obj import FileTransferMethod
 from core.ops.ops_trace_manager import TraceQueueManager
@@ -157,7 +156,7 @@ class ToolEngine:
             response = tool.invoke(user_id=user_id, tool_parameters=tool_parameters)
 
             # hit the callback handler
-            workflow_tool_callback.on_tool_end(
+            response = workflow_tool_callback.on_tool_execution(
                 tool_name=tool.entity.identity.name,
                 tool_inputs=tool_parameters,
                 tool_outputs=response,
@@ -168,31 +167,6 @@ class ToolEngine:
             workflow_tool_callback.on_tool_error(e)
             raise e
 
-    @staticmethod
-    def plugin_invoke(
-        tool: Tool, tool_parameters: dict, user_id: str, callback: DifyPluginCallbackHandler
-    ) -> Generator[ToolInvokeMessage, None, None]:
-        """
-        Plugin invokes the tool with the given arguments.
-        """
-        try:
-            # hit the callback handler
-            callback.on_tool_start(tool_name=tool.entity.identity.name, tool_inputs=tool_parameters)
-
-            response = tool.invoke(user_id, tool_parameters)
-
-            # hit the callback handler
-            callback.on_tool_end(
-                tool_name=tool.entity.identity.name,
-                tool_inputs=tool_parameters,
-                tool_outputs=response,
-            )
-
-            return response
-        except Exception as e:
-            callback.on_tool_error(e)
-            raise e
-
     @staticmethod
     def _invoke(
         tool: Tool, tool_parameters: dict, user_id: str