fix: LLMChain no output when no tools selected

server/callback_handler/agent_callback_handler.py

@@ -19,7 +19,7 @@ class AgentStatus:
     llm_end: int = 3
     agent_action: int = 4
     agent_finish: int = 5
-    tool_begin: int = 6
+    tool_start: int = 6
     tool_end: int = 7
     error: int = 8
 
@@ -59,10 +59,28 @@ class AgentExecutorAsyncIteratorCallbackHandler(AsyncIteratorCallbackHandler):
             }
             self.queue.put_nowait(dumps(data))
 
+    async def on_chat_model_start(
+            self,
+            serialized: Dict[str, Any],
+            messages: List[List],
+            *,
+            run_id: UUID,
+            parent_run_id: Optional[UUID] = None,
+            tags: Optional[List[str]] = None,
+            metadata: Optional[Dict[str, Any]] = None,
+            **kwargs: Any,
+    ) -> None:
+        data = {
+            "status": AgentStatus.llm_start,
+            "text": "",
+        }
+        self.done.clear()
+        self.queue.put_nowait(dumps(data))
+
     async def on_llm_end(self, response: LLMResult, **kwargs: Any) -> None:
         data = {
             "status": AgentStatus.llm_end,
-            "text": "",
+            "text": response.generations[0][0].message.content,
         }
         self.queue.put_nowait(dumps(data))
 
@@ -84,7 +102,7 @@ class AgentExecutorAsyncIteratorCallbackHandler(AsyncIteratorCallbackHandler):
             metadata: Optional[Dict[str, Any]] = None,
             **kwargs: Any,
     ) -> None:
-        print("tool_begin")
+        print("tool_start")
 
     async def on_tool_end(
             self,
@@ -100,7 +118,7 @@ class AgentExecutorAsyncIteratorCallbackHandler(AsyncIteratorCallbackHandler):
             "status": AgentStatus.tool_end,
             "tool_output": output,
         }
-        self.done.clear()
+        # self.done.clear()
         self.queue.put_nowait(dumps(data))
 
     async def on_tool_error(
@@ -117,7 +135,7 @@ class AgentExecutorAsyncIteratorCallbackHandler(AsyncIteratorCallbackHandler):
             "status": AgentStatus.tool_end,
             "text": error,
         }
-        self.done.clear()
+        # self.done.clear()
         self.queue.put_nowait(dumps(data))
 
     async def on_agent_action(
@@ -142,7 +160,6 @@ class AgentExecutorAsyncIteratorCallbackHandler(AsyncIteratorCallbackHandler):
             tags: Optional[List[str]] = None,
             **kwargs: Any,
     ) -> None:
-
         if "Thought:" in finish.return_values["output"]:
             finish.return_values["output"] = finish.return_values["output"].replace("Thought:", "")
 

server/chat/chat.py

@@ -113,6 +113,7 @@ def create_models_chains(history, history_len, prompts, models, tools, callbacks
         # full_chain = ({"topic": classifier_chain, "input": lambda x: x["input"]} | branch)
         full_chain = ({"input": lambda x: x["input"]} | agent_executor)
     else:
+        chain.llm.callbacks = callbacks
         full_chain = ({"input": lambda x: x["input"]} | chain)
     return full_chain
 

tests/test_qwen_agent.py

@@ -15,8 +15,9 @@ from langchain import globals
 
 async def main():
     callback = AgentExecutorAsyncIteratorCallbackHandler()
+    tools = [t.copy(update={"callbacks": [callback]}) for t in all_tools]
     qwen_model = get_ChatOpenAI("Qwen-1_8B-Chat", 0.01, streaming=True, callbacks=[callback])
-    executor = initialize_qwen_agent(tools=all_tools,
+    executor = initialize_qwen_agent(tools=tools,
                                      llm=qwen_model,
                                      callbacks=[callback],
                                      )