diff --git a/src/google/adk/telemetry/_metrics.py b/src/google/adk/telemetry/_metrics.py
index be5df9d494..4dbb27b358 100644
--- a/src/google/adk/telemetry/_metrics.py
+++ b/src/google/adk/telemetry/_metrics.py
@@ -99,6 +99,7 @@
     unit="1",
     description="Number of inference (model) calls per agent invocation.",
     explicit_bucket_boundaries_advisory=[
+        0,
         1,
         2,
         3,
@@ -118,6 +119,7 @@
     unit="1",
     description="Number of tool calls per agent invocation.",
     explicit_bucket_boundaries_advisory=[
+        0,
         1,
         2,
         3,