diff --git a/src/inputs/plugins/mock_input.py b/src/inputs/plugins/mock_input.py
index b7e994836..f496b9233 100644
--- a/src/inputs/plugins/mock_input.py
+++ b/src/inputs/plugins/mock_input.py
@@ -256,7 +256,7 @@ def formatted_latest_buffer(self) -> Optional[str]:
         result = f"""
 INPUT: {self.descriptor_for_LLM}
 // START
-{self.messages[-1]}
+{self.messages[-1].message}
 // END
 """
         self.io_provider.add_input(