diff --git a/src/ii_agent/agents/models/google/interactions.py b/src/ii_agent/agents/models/google/interactions.py
index a8578cc72..b06893497 100644
--- a/src/ii_agent/agents/models/google/interactions.py
+++ b/src/ii_agent/agents/models/google/interactions.py
@@ -978,7 +978,7 @@ def _get_metrics(self, response_usage: Usage) -> Metrics:
         metrics.reasoning_tokens = response_usage.total_thought_tokens or 0
         metrics.total_tokens = response_usage.total_tokens
 
-        metrics.cache_read_tokens = response_usage.total_cached_tokens
+        metrics.cache_read_tokens = response_usage.total_cached_tokens or 0
         # raw metrics
         metrics.additional_metrics = response_usage.model_dump()
         return metrics
diff --git a/src/tests/unit/engine/test_v1_models_google_interactions.py b/src/tests/unit/engine/test_v1_models_google_interactions.py
index 8e84dcbc3..2fbf42df6 100644
--- a/src/tests/unit/engine/test_v1_models_google_interactions.py
+++ b/src/tests/unit/engine/test_v1_models_google_interactions.py
@@ -773,6 +773,10 @@ def test_cache_read_tokens(self):
         gi = _make_gi()
         assert gi._get_metrics(_make_usage(cached_t=30)).cache_read_tokens == 30
 
+    def test_cache_read_tokens_none(self):
+        gi = _make_gi()
+        assert gi._get_metrics(_make_usage(cached_t=None)).cache_read_tokens == 0
+
     def test_additional_metrics_populated(self):
         gi = _make_gi()
         assert gi._get_metrics(_make_usage()).additional_metrics is not None