diff --git a/api/core/tools/tool_engine.py b/api/core/tools/tool_engine.py
index 178f2b968..83444c02d 100644
--- a/api/core/tools/tool_engine.py
+++ b/api/core/tools/tool_engine.py
@@ -29,7 +29,7 @@ from core.tools.errors import (
     ToolProviderCredentialValidationError,
     ToolProviderNotFoundError,
 )
-from core.tools.utils.message_transformer import ToolFileMessageTransformer
+from core.tools.utils.message_transformer import ToolFileMessageTransformer, safe_json_value
 from core.tools.workflow_as_tool.tool import WorkflowTool
 from extensions.ext_database import db
 from models.enums import CreatorUserRole
@@ -247,7 +247,8 @@ class ToolEngine:
                 )
             elif response.type == ToolInvokeMessage.MessageType.JSON:
                 result += json.dumps(
-                    cast(ToolInvokeMessage.JsonMessage, response.message).json_object, ensure_ascii=False
+                    safe_json_value(cast(ToolInvokeMessage.JsonMessage, response.message).json_object),
+                    ensure_ascii=False,
                 )
             else:
                 result += str(response.message)
diff --git a/api/core/tools/utils/message_transformer.py b/api/core/tools/utils/message_transformer.py
index 9998de046..ac12d83ef 100644
--- a/api/core/tools/utils/message_transformer.py
+++ b/api/core/tools/utils/message_transformer.py
@@ -1,7 +1,14 @@
 import logging
 from collections.abc import Generator
+from datetime import date, datetime
+from decimal import Decimal
 from mimetypes import guess_extension
-from typing import Optional
+from typing import Optional, cast
+from uuid import UUID
+
+import numpy as np
+import pytz
+from flask_login import current_user
 
 from core.file import File, FileTransferMethod, FileType
 from core.tools.entities.tool_entities import ToolInvokeMessage
@@ -10,6 +17,41 @@ from core.tools.tool_file_manager import ToolFileManager
 logger = logging.getLogger(__name__)
 
 
+def safe_json_value(v):
+    if isinstance(v, datetime):
+        tz_name = getattr(current_user, "timezone", None) if current_user is not None else None
+        if not tz_name:
+            tz_name = "UTC"
+        return v.astimezone(pytz.timezone(tz_name)).isoformat()
+    elif isinstance(v, date):
+        return v.isoformat()
+    elif isinstance(v, UUID):
+        return str(v)
+    elif isinstance(v, Decimal):
+        return float(v)
+    elif isinstance(v, bytes):
+        try:
+            return v.decode("utf-8")
+        except UnicodeDecodeError:
+            return v.hex()
+    elif isinstance(v, memoryview):
+        return v.tobytes().hex()
+    elif isinstance(v, np.ndarray):
+        return v.tolist()
+    elif isinstance(v, dict):
+        return safe_json_dict(v)
+    elif isinstance(v, list | tuple | set):
+        return [safe_json_value(i) for i in v]
+    else:
+        return v
+
+
+def safe_json_dict(d):
+    if not isinstance(d, dict):
+        raise TypeError("safe_json_dict() expects a dictionary (dict) as input")
+    return {k: safe_json_value(v) for k, v in d.items()}
+
+
 class ToolFileMessageTransformer:
     @classmethod
     def transform_tool_invoke_messages(
@@ -113,6 +155,12 @@ class ToolFileMessageTransformer:
                             )
                     else:
                         yield message
+
+            elif message.type == ToolInvokeMessage.MessageType.JSON:
+                if isinstance(message.message, ToolInvokeMessage.JsonMessage):
+                    json_msg = cast(ToolInvokeMessage.JsonMessage, message.message)
+                    json_msg.json_object = safe_json_value(json_msg.json_object)
+                yield message
             else:
                 yield message