diff --git a/test_bot/buggy_engine.py b/test_bot/buggy_engine.py
index b5add5aff..81908c211 100644
--- a/test_bot/buggy_engine.py
+++ b/test_bot/buggy_engine.py
@@ -5,9 +5,12 @@
 
 assert input() == "uci"
 
+
 def send_command(command: str) -> None:
+    """Send UCI commands to lichess-bot without output buffering."""
     print(command, flush=True)
 
+
 send_command("id name Procrastinator")
 send_command("id author MZH")
 send_command("uciok")