diff --git a/src/agentunit/generators/llm_generator.py b/src/agentunit/generators/llm_generator.py
index 836f011..24c6f67 100644
--- a/src/agentunit/generators/llm_generator.py
+++ b/src/agentunit/generators/llm_generator.py
@@ -141,7 +141,7 @@ async def generate(
 
             cases_data = json.loads(response_text)
 
-            cases = []
+            cases: list[DatasetCase] = []
             for case_data in cases_data:
                 case = DatasetCase(
                     id=case_data.get("id", f"generated_{len(cases)}"),
@@ -288,7 +288,7 @@ async def generate(
 
             cases_data = json.loads(response_text)
 
-            cases = []
+            cases: list[DatasetCase] = []
             for case_data in cases_data:
                 case = DatasetCase(
                     id=case_data.get("id", f"generated_{len(cases)}"),