diff --git a/dingdingflow/init.py b/dingdingflow/init.py
index 5207faa..55b00e1 100644
--- a/dingdingflow/init.py
+++ b/dingdingflow/init.py
@@ -185,6 +185,14 @@ async def submit_approval(biz_type, biz_id, title, applicant_id, org_id='0'):
     """
     client = get_dingtalk_client()
 
+    # 无钉钉凭据（未对接）：明确报失败让调用方降级人工审批。
+    # ⚠️ 不能返回 mock 成功——假实例无人可审，回调永不到达，审批会永久卡死。
+    if client.is_dev_mode:
+        logger.warning('DingTalk credentials not configured, biz_type=%s '
+                       'should fall back to human approval', biz_type)
+        return {'success': False,
+                'message': 'DingTalk not configured (missing DINGTALK_APP_KEY/SECRET)'}
+
     # 查找审批配置
     config = await get_approval_config_by_type(org_id, biz_type)
     if not config: