diff --git a/src/plugins/heartFC_chat/heartFC_generator.py b/src/plugins/heartFC_chat/heartFC_generator.py
index 464e94e91..da43c334f 100644
--- a/src/plugins/heartFC_chat/heartFC_generator.py
+++ b/src/plugins/heartFC_chat/heartFC_generator.py
@@ -78,7 +78,7 @@ class HeartFCGenerator:
     ) -> str:
         info_catcher = info_catcher_manager.get_info_catcher(thinking_id)
 
-        with Timer() as t_build_prompt:
+        with Timer() as _build_prompt:
             prompt = await prompt_builder.build_prompt(
                 build_mode="focus",
                 reason=reason,