diff --git a/agent/tools/retrieval.py b/agent/tools/retrieval.py
index c3a01e517..fd9096cb6 100644
--- a/agent/tools/retrieval.py
+++ b/agent/tools/retrieval.py
@@ -137,7 +137,7 @@ class Retrieval(ToolBase, ABC):
                 if not doc_ids:
                     doc_ids = None
             elif self._param.meta_data_filter.get("method") == "manual":
-                filters=self._param.meta_data_filter["manual"]
+                filters = self._param.meta_data_filter["manual"]
                 for flt in filters:
                     pat = re.compile(self.variable_ref_patt)
                     s = flt["value"]
@@ -166,8 +166,8 @@ class Retrieval(ToolBase, ABC):
                     out_parts.append(s[last:])
                     flt["value"] = "".join(out_parts)
                 doc_ids.extend(meta_filter(metas, filters, self._param.meta_data_filter.get("logic", "and")))
-                if not doc_ids:
-                    doc_ids = None
+                if filters and not doc_ids:
+                    doc_ids = ["-999"]
 
         if self._param.cross_languages:
             query = cross_languages(kbs[0].tenant_id, None, query, self._param.cross_languages)
diff --git a/api/apps/chunk_app.py b/api/apps/chunk_app.py
index e121bcba7..b43fb9af1 100644
--- a/api/apps/chunk_app.py
+++ b/api/apps/chunk_app.py
@@ -311,8 +311,8 @@ async def retrieval_test():
                 doc_ids = None
         elif meta_data_filter.get("method") == "manual":
             doc_ids.extend(meta_filter(metas, meta_data_filter["manual"], meta_data_filter.get("logic", "and")))
-            if not doc_ids:
-                doc_ids = None
+            if meta_data_filter["manual"] and not doc_ids:
+                doc_ids = ["-999"]
 
     try:
         tenants = UserTenantService.query(user_id=current_user.id)
diff --git a/api/apps/sdk/doc.py b/api/apps/sdk/doc.py
index 84300ac3c..30fbd835e 100644
--- a/api/apps/sdk/doc.py
+++ b/api/apps/sdk/doc.py
@@ -1445,6 +1445,8 @@ async def retrieval_test(tenant_id):
         metadata_condition = req.get("metadata_condition", {}) or {}
         metas = DocumentService.get_meta_by_kbs(kb_ids)
         doc_ids = meta_filter(metas, convert_conditions(metadata_condition), metadata_condition.get("logic", "and"))
+        if metadata_condition and not doc_ids:
+            doc_ids = ["-999"]
     similarity_threshold = float(req.get("similarity_threshold", 0.2))
     vector_similarity_weight = float(req.get("vector_similarity_weight", 0.3))
     top = int(req.get("top_k", 1024))
diff --git a/api/apps/sdk/session.py b/api/apps/sdk/session.py
index 533375622..074401ede 100644
--- a/api/apps/sdk/session.py
+++ b/api/apps/sdk/session.py
@@ -446,8 +446,8 @@ async def agent_completions(tenant_id, agent_id):
 
     if req.get("stream", True):
 
-        def generate():
-            for answer in agent_completion(tenant_id=tenant_id, agent_id=agent_id, **req):
+        async def generate():
+            async for answer in agent_completion(tenant_id=tenant_id, agent_id=agent_id, **req):
                 if isinstance(answer, str):
                     try:
                         ans = json.loads(answer[5:])  # remove "data:"
@@ -471,7 +471,7 @@ async def agent_completions(tenant_id, agent_id):
     full_content = ""
     reference = {}
     final_ans = ""
-    for answer in agent_completion(tenant_id=tenant_id, agent_id=agent_id, **req):
+    async for answer in agent_completion(tenant_id=tenant_id, agent_id=agent_id, **req):
         try:
             ans = json.loads(answer[5:])
 
@@ -873,7 +873,7 @@ async def agent_bot_completions(agent_id):
         resp.headers.add_header("Content-Type", "text/event-stream; charset=utf-8")
         return resp
 
-    for answer in agent_completion(objs[0].tenant_id, agent_id, **req):
+    async for answer in agent_completion(objs[0].tenant_id, agent_id, **req):
         return get_result(data=answer)
 
 
@@ -981,8 +981,8 @@ async def retrieval_test_embedded():
                 doc_ids = None
         elif meta_data_filter.get("method") == "manual":
             doc_ids.extend(meta_filter(metas, meta_data_filter["manual"], meta_data_filter.get("logic", "and")))
-            if not doc_ids:
-                doc_ids = None
+            if meta_data_filter["manual"] and not doc_ids:
+                doc_ids = ["-999"]
 
     try:
         tenants = UserTenantService.query(user_id=tenant_id)
diff --git a/api/db/services/dialog_service.py b/api/db/services/dialog_service.py
index db878574d..0a09ea532 100644
--- a/api/db/services/dialog_service.py
+++ b/api/db/services/dialog_service.py
@@ -415,9 +415,10 @@ def chat(dialog, messages, stream=True, **kwargs):
             if not attachments:
                 attachments = None
         elif dialog.meta_data_filter.get("method") == "manual":
-            attachments.extend(meta_filter(metas, dialog.meta_data_filter["manual"], dialog.meta_data_filter.get("logic", "and")))
-            if not attachments:
-                attachments = None
+            conds = dialog.meta_data_filter["manual"]
+            attachments.extend(meta_filter(metas, conds, dialog.meta_data_filter.get("logic", "and")))
+            if conds and not attachments:
+                attachments = ["-999"]
 
     if prompt_config.get("keyword", False):
         questions[-1] += keyword_extraction(chat_mdl, questions[-1])
@@ -787,8 +788,8 @@ def ask(question, kb_ids, tenant_id, chat_llm_name=None, search_config={}):
                 doc_ids = None
         elif meta_data_filter.get("method") == "manual":
             doc_ids.extend(meta_filter(metas, meta_data_filter["manual"], meta_data_filter.get("logic", "and")))
-            if not doc_ids:
-                doc_ids = None
+            if meta_data_filter["manual"] and not doc_ids:
+                doc_ids = ["-999"]
 
     kbinfos = retriever.retrieval(
         question=question,
@@ -862,8 +863,8 @@ def gen_mindmap(question, kb_ids, tenant_id, search_config={}):
                 doc_ids = None
         elif meta_data_filter.get("method") == "manual":
             doc_ids.extend(meta_filter(metas, meta_data_filter["manual"], meta_data_filter.get("logic", "and")))
-            if not doc_ids:
-                doc_ids = None
+            if meta_data_filter["manual"] and not doc_ids:
+                doc_ids = ["-999"]
 
     ranks = settings.retriever.retrieval(
         question=question,