diff --git a/stockcli/cli.py b/stockcli/cli.py
--- a/stockcli/cli.py
+++ b/stockcli/cli.py
@@ -26,6 +26,7 @@ TASK_MAP = {
     "3": ("Update stock", update_by_barcode),
     "4": ("Get product info", get_info_by_barcode),
     "5": ("Add book", add_book_by_barcode),
+    "6": ("Update ISBN", update_isbn),
 }