diff --git a/src/memos/api/handlers/chat_handler.py b/src/memos/api/handlers/chat_handler.py
index caeba0ca1..812cf2793 100644
--- a/src/memos/api/handlers/chat_handler.py
+++ b/src/memos/api/handlers/chat_handler.py
@@ -482,7 +482,7 @@ def generate_chat_response() -> Generator[str, None, None]:
                     # get preference string
                     pref_string = search_response.data.get("pref_string", "")
 
-                    yield f"data: {json.dumps({'type': 'reference', 'data': reference})}\n\n"
+                    yield f"data: {json.dumps({'type': 'reference', 'data': reference}, ensure_ascii=False)}\n\n"
 
                     # Prepare preference markdown string
                     if chat_req.include_preference:
@@ -586,7 +586,7 @@ def generate_chat_response() -> Generator[str, None, None]:
                     internet_reference = self._get_internet_reference(
                         search_response.data.get("text_mem")[0]["memories"]
                     )
-                    yield f"data: {json.dumps({'type': 'reference', 'data': reference})}\n\n"
+                    yield f"data: {json.dumps({'type': 'reference', 'data': reference}, ensure_ascii=False)}\n\n"
 
                     # Step 2: Build system prompt with memories
                     lang = detect_lang(chat_req.query)
@@ -684,7 +684,7 @@ def generate_chat_response() -> Generator[str, None, None]:
 
                     if chat_req.internet_search or parsed_goal.internet_search:
                         # Yield internet reference after text response
-                        yield f"data: {json.dumps({'type': 'internet_reference', 'data': internet_reference})}\n\n"
+                        yield f"data: {json.dumps({'type': 'internet_reference', 'data': internet_reference}, ensure_ascii=False)}\n\n"
 
                     # Calculate timing
                     time_end = time.time()
@@ -697,7 +697,7 @@ def generate_chat_response() -> Generator[str, None, None]:
                     current_messages.append({"role": "assistant", "content": full_response})
                     further_suggestion = self._get_further_suggestion(current_messages)
                     self.logger.info(f"[PLAYGROUND CHAT] further_suggestion: {further_suggestion}")
-                    yield f"data: {json.dumps({'type': 'suggestion', 'data': further_suggestion})}\n\n"
+                    yield f"data: {json.dumps({'type': 'suggestion', 'data': further_suggestion}, ensure_ascii=False)}\n\n"
 
                     yield f"data: {json.dumps({'type': 'end'})}\n\n"
 
diff --git a/src/memos/api/product_models.py b/src/memos/api/product_models.py
index f0a4e333b..ee7a45c2d 100644
--- a/src/memos/api/product_models.py
+++ b/src/memos/api/product_models.py
@@ -1197,3 +1197,13 @@ class GetUserNamesByMemoryIdsRequest(BaseRequest):
 
 class GetUserNamesByMemoryIdsResponse(BaseResponse[dict[str, str | None]]):
     """Response model for getting user names by memory ids."""
+
+
+class ExistMemCubeIdRequest(BaseRequest):
+    """Request model for checking if mem cube id exists."""
+
+    mem_cube_id: str = Field(..., description="Mem cube ID")
+
+
+class ExistMemCubeIdResponse(BaseResponse[dict[str, bool]]):
+    """Response model for checking if mem cube id exists."""
diff --git a/src/memos/api/routers/server_router.py b/src/memos/api/routers/server_router.py
index 7c0f3ea8f..c60e84253 100644
--- a/src/memos/api/routers/server_router.py
+++ b/src/memos/api/routers/server_router.py
@@ -33,6 +33,8 @@
     ChatRequest,
     DeleteMemoryRequest,
     DeleteMemoryResponse,
+    ExistMemCubeIdRequest,
+    ExistMemCubeIdResponse,
     GetMemoryPlaygroundRequest,
     GetMemoryRequest,
     GetMemoryResponse,
@@ -362,3 +364,17 @@ def get_user_names_by_memory_ids(request: GetUserNamesByMemoryIdsRequest):
         message="Successfully",
         data=result,
     )
+
+
+@router.post(
+    "/exist_mem_cube_id",
+    summary="Check if mem cube id exists",
+    response_model=ExistMemCubeIdResponse,
+)
+def exist_mem_cube_id(request: ExistMemCubeIdRequest):
+    """Check if mem cube id exists."""
+    return ExistMemCubeIdResponse(
+        code=200,
+        message="Successfully",
+        data=graph_db.exist_user_name(user_name=request.mem_cube_id),
+    )
diff --git a/src/memos/memories/textual/tree_text_memory/retrieve/utils.py b/src/memos/memories/textual/tree_text_memory/retrieve/utils.py
index bcd47b078..54caa20f7 100644
--- a/src/memos/memories/textual/tree_text_memory/retrieve/utils.py
+++ b/src/memos/memories/textual/tree_text_memory/retrieve/utils.py
@@ -27,7 +27,7 @@
   "tags": [...],
   "goal_type": "retrieval | qa | generation",
   "rephrased_instruction": "...", # return an empty string if the original instruction is easy enough to understand
-  "internet_search": True/False,
+  "internet_search": true/false,
   "memories": ["...", "...", ...]
 }
 """