diff --git a/examples/quick_start.py b/examples/quick_start.py
index 3f128552..9fa32154 100644
--- a/examples/quick_start.py
+++ b/examples/quick_start.py
@@ -60,7 +60,11 @@ async def with_tools_example():
             for block in message.content:
                 if isinstance(block, TextBlock):
                     print(f"Claude: {block.text}")
-        elif isinstance(message, ResultMessage) and message.total_cost_usd > 0:
+        elif (
+            isinstance(message, ResultMessage)
+            and message.total_cost_usd
+            and message.total_cost_usd > 0
+        ):
             print(f"\nCost: ${message.total_cost_usd:.4f}")
     print()