添加rag置信度判断

backend/app/main_graph/main_graph_builder.py

@@ -21,15 +21,15 @@ from .nodes.fast_paths import (
     fast_tool_node,
 )
 from .nodes.llm_call import create_dynamic_llm_call_node
-from .nodes.rag_nodes import rag_retrieve_node
+from .nodes.rag_nodes import rag_retrieve_node, check_rag_confidence
 from .nodes.retrieve_memory import create_retrieve_memory_node
 from .nodes.memory_trigger import memory_trigger_node, set_mem0_client
 from .nodes.summarize import create_summarize_node
 from .nodes.finalize import finalize_node
-from ..subgraphs.contact import build_contact_subgraph
-from ..subgraphs.dictionary import build_dictionary_subgraph
-from ..subgraphs.news_analysis import build_news_analysis_subgraph
-from ..logger import info
+from backend.app.subgraphs.contact import build_contact_subgraph
+from backend.app.subgraphs.dictionary import build_dictionary_subgraph
+from backend.app.subgraphs.news_analysis import build_news_analysis_subgraph
+from backend.app.logger import info
 
 from .subgraph_wrapper import create_subgraph_nodes
 
@@ -198,8 +198,20 @@ def _add_react_loop_edges(graph: StateGraph, subgraph_nodes: Dict[str, Any]) ->
         }
     )
 
+    # RAG 检索后的置信度判断分支
+    graph.add_conditional_edges(
+        "rag_retrieve",
+        check_rag_confidence,
+        {
+            "high_confidence": "llm_call",      # 高置信度 → 直接生成回答
+            "retry_rag": "rag_retrieve",         # 低置信度 → 再次检索
+            "low_confidence": "web_search",      # 两次RAG后仍低 → 联网搜索
+            "no_rag": "web_search",             # 无结果 → 联网搜索
+        }
+    )
+
     # 循环边（回到 react_reason）
-    loop_back_nodes = ["rag_retrieve", "web_search", "handle_error"] + subgraph_names
+    loop_back_nodes = ["web_search", "handle_error"] + subgraph_names
     for node_name in loop_back_nodes:
         graph.add_edge(node_name, "react_reason")