diff --git a/openhands/llm/metrics.py b/openhands/llm/metrics.py
index f3f2a4e4b4c3..a010bb26916d 100644
--- a/openhands/llm/metrics.py
+++ b/openhands/llm/metrics.py
@@ -46,8 +46,14 @@ def costs(self) -> list[Cost]:
 
     @property
     def response_latencies(self) -> list[ResponseLatency]:
+        if not hasattr(self, '_response_latencies'):
+            self._response_latencies = []
         return self._response_latencies
 
+    @response_latencies.setter
+    def response_latencies(self, value: list[ResponseLatency]) -> None:
+        self._response_latencies = value
+
     def add_cost(self, value: float) -> None:
         if value < 0:
             raise ValueError('Added cost cannot be negative.')