diff --git a/src/mistral_common/protocol/instruct/normalize.py b/src/mistral_common/protocol/instruct/normalize.py
index a151855..c877ee8 100644
--- a/src/mistral_common/protocol/instruct/normalize.py
+++ b/src/mistral_common/protocol/instruct/normalize.py
@@ -117,7 +117,7 @@ def _aggregate_assistant_messages(self, messages: List[UATS]) -> AssistantMessag
         weight: Optional[float] = None
         for message in messages:
             assert isinstance(message, self._assistant_message_class), "Expected assistant message"
-            if message.tool_calls is not None:
+            if message.tool_calls:
                 for tool_call in message.tool_calls:
                     normalized_tool_call = self._normalize_tool_call(tool_call)
                     tool_calls.append(normalized_tool_call)
diff --git a/tests/test_normalization.py b/tests/test_normalization.py
index 9637a18..da11bf8 100644
--- a/tests/test_normalization.py
+++ b/tests/test_normalization.py
@@ -293,6 +293,10 @@ def test_normalize_funcalls(self, normalizer: InstructRequestNormalizer) -> None
         normalized = normalizer.from_chat_completion_request(request)
         assert normalized == gt
 
+    def test_normalize_empty_array_tool_calls(self, normalizer: InstructRequestNormalizer) -> None:
+        message = AssistantMessage(role="assistant", content="Hello", tool_calls=[])
+        normalized_message = normalizer._aggregate_assistant_messages([message])
+        assert normalized_message.content == "Hello"
 
 class TestFineTuningNormalizer:
     @pytest.fixture(autouse=True)