fix: 修复 _generate_node 中 messages[-3] 硬编码索引在多工具调用场景下的潜在问题

graphrag_agent/agents/base.py

@@ -112,6 +112,25 @@ class AgentState(TypedDict):
         # 编译图
         self.graph = workflow.compile(checkpointer=self.memory)
 
+    @staticmethod
+    def _find_last_human_message(messages):
+        """
+        从 messages 列表中查找最后一条 HumanMessage。
+
+        使用类型匹配代替硬编码索引 messages[-3]，
+        避免在多工具调用或多轮对话场景下取到错误内容。
+
+        参数:
+            messages: 消息列表
+
+        返回:
+            HumanMessage 或 None
+        """
+        for msg in reversed(messages):
+            if isinstance(msg, HumanMessage):
+                return msg
+        return None
+
     async def _stream_process(self, inputs: Dict[str, Any], config: Dict[str, Any]) -> AsyncGenerator[str, None]:
         """
         执行流式处理的默认实现

graphrag_agent/agents/deep_research_agent.py

@@ -128,9 +128,9 @@ def _generate_node(self, state):
         messages = state["messages"]
 
         # 安全地获取问题和检索结果
+        human_msg = self._find_last_human_message(messages)
+        question = human_msg.content if human_msg else "未找到问题"
         try:
-            # 原始问题在倒数第三个消息
-            question = messages[-3].content if len(messages) >= 3 else "未找到问题"
             # 检索结果在最后一个消息
             retrieval_result = messages[-1].content if messages[-1] else "未找到相关信息"
         except Exception as e:

graphrag_agent/agents/graph_agent.py

@@ -121,11 +121,14 @@ def _grade_documents(self, state) -> str:
             return "reduce"
 
         # 获取问题和文档内容
+        human_msg = self._find_last_human_message(messages)
+        if not human_msg:
+            print("文档评分出错: 未找到用户问题")
+            return "generate"
+        question = human_msg.content
         try:
-            question = messages[-3].content
             docs = messages[-1].content
         except Exception as e:
-            # 如果出错，默认为 generate 模式
             print(f"文档评分出错: {e}")
             return "generate"
 
@@ -143,8 +146,8 @@ def _grade_documents(self, state) -> str:
 
         # 从问题中提取关键词
         keywords = []
-        if hasattr(messages[-3], 'additional_kwargs') and messages[-3].additional_kwargs:
-            kw_data = messages[-3].additional_kwargs.get("keywords", {})
+        if human_msg and hasattr(human_msg, 'additional_kwargs') and human_msg.additional_kwargs:
+            kw_data = human_msg.additional_kwargs.get("keywords", {})
             if isinstance(kw_data, dict):
                 keywords = kw_data.get("low_level", []) + kw_data.get("high_level", [])
 
@@ -171,7 +174,8 @@ def _grade_documents(self, state) -> str:
     def _generate_node(self, state):
         """生成回答节点逻辑"""
         messages = state["messages"]
-        question = messages[-3].content
+        human_msg = self._find_last_human_message(messages)
+        question = human_msg.content if human_msg else "未找到问题"
         docs = messages[-1].content
 
         # 首先尝试全局缓存
@@ -221,7 +225,8 @@ def _generate_node(self, state):
     def _reduce_node(self, state):
         """处理全局搜索的Reduce节点逻辑"""
         messages = state["messages"]
-        question = messages[-3].content
+        human_msg = self._find_last_human_message(messages)
+        question = human_msg.content if human_msg else "未找到问题"
         docs = messages[-1].content
 
         # 检查缓存
@@ -259,7 +264,8 @@ async def _generate_node_stream(self, state):
 
         # 安全获取问题和文档内容
         try:
-            question = messages[-3].content if len(messages) >= 3 else "未找到问题"
+            human_msg = self._find_last_human_message(messages)
+            question = human_msg.content if human_msg else "未找到问题"
             docs = messages[-1].content if messages[-1] else "未找到相关信息"
         except Exception as e:
             yield f"**获取问题或文档时出错**: {str(e)}"

graphrag_agent/agents/hybrid_agent.py

@@ -74,10 +74,8 @@ def _generate_node(self, state):
         messages = state["messages"]
 
         # 安全地获取问题内容
-        try:
-            question = messages[-3].content if len(messages) >= 3 else "未找到问题"
-        except Exception:
-            question = "无法获取问题"
+        human_msg = self._find_last_human_message(messages)
+        question = human_msg.content if human_msg else "未找到问题"
 
         # 安全地获取文档内容
         try:
@@ -143,10 +141,8 @@ async def _generate_node_stream(self, state):
         messages = state["messages"]
 
         # 安全地获取问题内容
-        try:
-            question = messages[-3].content if len(messages) >= 3 else "未找到问题"
-        except Exception:
-            question = "无法获取问题"
+        human_msg = self._find_last_human_message(messages)
+        question = human_msg.content if human_msg else "未找到问题"
 
         # 安全地获取文档内容
         try:

graphrag_agent/agents/naive_rag_agent.py

@@ -53,10 +53,8 @@ def _generate_node(self, state):
         messages = state["messages"]
 
         # 安全地获取问题和检索结果
-        try:
-            question = messages[-3].content if len(messages) >= 3 else "未找到问题"
-        except Exception:
-            question = "无法获取问题"
+        human_msg = self._find_last_human_message(messages)
+        question = human_msg.content if human_msg else "未找到问题"
 
         try:
             docs = messages[-1].content if messages[-1] else "未找到相关信息"