diff --git a/slot_change_stream.py b/slot_change_stream.py
index e7332d2..72ad8a8 100644
--- a/slot_change_stream.py
+++ b/slot_change_stream.py
@@ -102,7 +102,9 @@ def stream(args):
 
     # Start from either user-specified block or tip
     current = args.start if args.start is not None else w3.eth.block_number
-    if current < 0: print("❌ start block cannot be negative."); sys.exit(2)
+        if current < 0:
+        print("❌ start block cannot be negative.", file=sys.stderr)
+        sys.exit(2)
 
     while not stop_flag["stop"]:
         if not w3.is_connected(): print("🔌 Reconnecting RPC…"); w3 = connect(args.rpc)