diff --git a/ads_mcp/utils.py b/ads_mcp/utils.py
index 7dd281a..160c73a 100644
--- a/ads_mcp/utils.py
+++ b/ads_mcp/utils.py
@@ -96,6 +96,10 @@ def get_googleads_client():
 def format_output_value(value: Any) -> Any:
     if isinstance(value, proto.Enum):
         return value.name
+    elif isinstance(value, proto.Message):
+        return proto.Message.to_dict(value)
+    elif isinstance(value, (list, tuple)):
+        return [format_output_value(item) for item in value]
     else:
         return value