diff --git a/src/daemon/health.py b/src/daemon/health.py
index ffb292b..449dc39 100644
--- a/src/daemon/health.py
+++ b/src/daemon/health.py
@@ -30,6 +30,8 @@ class HealthChecker:
         self._stale_ticks: Dict[str, int] = {}
         # project_id → 是否已告警
         self._alerted: Dict[str, bool] = {}
+        # project_id → 上次检查时的 event count
+        self._last_event_count: Dict[str, int] = {}
 
     def check(self, project_id: str, db_path: Path,
               tick_num: int) -> Dict[str, Any]: