diff --git a/api/core/features/assistant_base_runner.py b/api/core/features/assistant_base_runner.py
index 1d9541070f881..aa15c45869b0d 100644
--- a/api/core/features/assistant_base_runner.py
+++ b/api/core/features/assistant_base_runner.py
@@ -566,7 +566,11 @@ def organize_agent_history(self, prompt_messages: list[PromptMessage]) -> list[P
                         tools = tools.split(';')
                         tool_calls: list[AssistantPromptMessage.ToolCall] = []
                         tool_call_response: list[ToolPromptMessage] = []
-                        tool_inputs = json.loads(agent_thought.tool_input)
+                        try:
+                            tool_inputs = json.loads(agent_thought.tool_input)
+                        except Exception as e:
+                            logging.warning("tool execution error: {}, tool_input: {}.".format(str(e), agent_thought.tool_input))
+                            tool_inputs = { agent_thought.tool: agent_thought.tool_input }
                         for tool in tools:
                             # generate a uuid for tool call
                             tool_call_id = str(uuid.uuid4())
@@ -599,4 +603,4 @@ def organize_agent_history(self, prompt_messages: list[PromptMessage]) -> list[P
 
         db.session.close()
 
-        return result
\ No newline at end of file
+        return result
diff --git a/api/core/features/assistant_cot_runner.py b/api/core/features/assistant_cot_runner.py
index 3762ddcf62e7c..6d43d846e473e 100644
--- a/api/core/features/assistant_cot_runner.py
+++ b/api/core/features/assistant_cot_runner.py
@@ -182,7 +182,7 @@ def increase_usage(final_llm_usage_dict: dict[str, LLMUsage], usage: LLMUsage):
                             delta=LLMResultChunkDelta(
                                 index=0,
                                 message=AssistantPromptMessage(
-                                    content=json.dumps(chunk)
+                                    content=json.dumps(chunk, ensure_ascii=False) # if ensure_ascii=True, the text in webui maybe garbled text
                                 ),
                                 usage=None
                             )
@@ -667,4 +667,4 @@ def _jsonify_tool_prompt_messages(self, tools: list[PromptMessageTool]) -> str:
         try:
             return json.dumps(tools, ensure_ascii=False)
         except json.JSONDecodeError:
-            return json.dumps(tools)
\ No newline at end of file
+            return json.dumps(tools)