diff --git a/app/services/ai_tool.py b/app/services/ai_tool.py
index 14f07db..9c6a68d 100644
--- a/app/services/ai_tool.py
+++ b/app/services/ai_tool.py
@@ -82,11 +82,10 @@ async def ai_chat(llm: BaseChatModel, system_prompt: str, user_message: str, sce
 
 
 async def _probe_until_recover(llm: BaseChatModel, system_prompt: str, user_message: str) -> str:
-    """探针：退避重试直到接口恢复，返回成功的响应内容，并打开门闸唤醒所有等待协程"""
+    """探针：固定间隔重试直到接口恢复，返回成功的响应内容，并打开门闸唤醒所有等待协程"""
     global _gate_probing
 
-    delay = 1.0  # 初始退避 1 秒
-    max_delay = 30.0  # 最大退避 30 秒
+    delay = 0.5  # 固定间隔 500ms
     attempt = 0
 
     while True:
@@ -104,8 +103,7 @@ async def _probe_until_recover(llm: BaseChatModel, system_prompt: str, user_mess
             log.info("AI 接口恢复，门闸打开，第{}次探测成功", attempt)
             return response.content
         except Exception as e:
-            log.warning("AI 接口仍不可用，第{}次探测失败(退避{}s): {}", attempt, delay, e)
-            delay = min(delay * 2, max_delay)
+            log.warning("AI 接口仍不可用，第{}次探测失败(间隔{}ms): {}", attempt, int(delay * 1000), e)
 
 
 async def ai_chat_json(llm: BaseChatModel, system_prompt: str, user_message: str, scene: Optional[str] = None) -> Any: