diff --git a/pipeline_service/agent_loop_v2.py b/pipeline_service/agent_loop_v2.py
index 5f9dde7..de4886e 100644
--- a/pipeline_service/agent_loop_v2.py
+++ b/pipeline_service/agent_loop_v2.py
@@ -1352,6 +1352,10 @@ class AgentExecutor:
 
             db = DBPools()
             async with db.sqlorContext("pipeline") as sor:
+                # 产线隔离（2026-08-31）：generic 会话不挂产线标签——generic 的
+                # pipeline_id 会回退 DEFAULT_ABILITY_ID(sdlc_general)，若落库会污染
+                # 开发产线历史。存空串 = 通用对话，各产线读取时按产线过滤自然排除。
+                store_pl = "" if self.generic else (self.pipeline_id or "")
                 # 用户消息
                 await sor.C("pipeline_conversations", {
                     "id": getID(),
@@ -1360,7 +1364,7 @@ class AgentExecutor:
                     "created_by": self.user_id or "",
                     "iteration_id": self.project_id or "",
                     "session_id": self.session_id or "",
-                    "pipeline_id": self.pipeline_id or "",
+                    "pipeline_id": store_pl,
                 })
                 # 助手回复（不含 tool_call JSON！）
                 reply_clean = reply
@@ -1373,7 +1377,7 @@ class AgentExecutor:
                     "created_by": self.user_id or "",
                     "iteration_id": self.project_id or "",
                     "session_id": self.session_id or "",
-                    "pipeline_id": self.pipeline_id or "",
+                    "pipeline_id": store_pl,
                 })
         except Exception as e:
             logger.warning(f"Session save failed: {e}")