diff --git a/app/bot_cli.py b/app/bot_cli.py
index 91c0dc0..8d725a9 100644
--- a/app/bot_cli.py
+++ b/app/bot_cli.py
@@ -23,6 +23,19 @@ def cmd_register(_args):
     _print_user(bot.get_user_api())
 
 
+def cmd_set_pin(args):
+    bot = CM_BOT_HAL()
+    if not bot.is_whatsapp_url(args.link):
+        print(f"ERROR: not a WhatsApp URL: {args.link}", file=sys.stderr)
+        sys.exit(2)
+    t_username, f_username = bot.get_whatsapp_link_username(args.link)
+    success = bot.set_security_pin_api(args.link)
+    if not success:
+        print("ERROR: set_security_pin_api returned a falsy result", file=sys.stderr)
+        sys.exit(1)
+    print(f"OK: f_username={f_username} t_username={t_username}")
+
+
 def build_parser() -> argparse.ArgumentParser:
     p = argparse.ArgumentParser(
         prog="bot_cli",
@@ -33,6 +46,10 @@ def build_parser() -> argparse.ArgumentParser:
     sp = sub.add_parser("register", aliases=["get-acc"], help="Get next available account (Telegram /1).")
     sp.set_defaults(func=cmd_register)
 
+    sp = sub.add_parser("set-pin", help="Set security PIN from a WhatsApp link (Telegram /2).")
+    sp.add_argument("link")
+    sp.set_defaults(func=cmd_set_pin)
+
     return p
 
 
diff --git a/tests/test_bot_cli.py b/tests/test_bot_cli.py
index 35f0d79..78377dd 100644
--- a/tests/test_bot_cli.py
+++ b/tests/test_bot_cli.py
@@ -65,5 +65,46 @@ class CmdRegisterTests(unittest.TestCase):
         self.assertIs(args.func, bot_cli.cmd_register)
 
 
+class CmdSetPinTests(unittest.TestCase):
+    @mock.patch.object(bot_cli, "CM_BOT_HAL")
+    def test_rejects_invalid_whatsapp_url(self, mock_hal_class):
+        mock_hal = mock_hal_class.return_value
+        mock_hal.is_whatsapp_url.return_value = False
+        with self.assertRaises(SystemExit) as cm:
+            bot_cli.cmd_set_pin(argparse.Namespace(link="https://not-whatsapp.example/x"))
+        self.assertEqual(cm.exception.code, 2)
+        mock_hal.set_security_pin_api.assert_not_called()
+
+    @mock.patch.object(bot_cli, "CM_BOT_HAL")
+    def test_extracts_names_locally_and_succeeds(self, mock_hal_class):
+        mock_hal = mock_hal_class.return_value
+        mock_hal.is_whatsapp_url.return_value = True
+        mock_hal.get_whatsapp_link_username.return_value = ("t_user_42", "f_user_42")
+        mock_hal.set_security_pin_api.return_value = True
+        out = io.StringIO()
+        with contextlib.redirect_stdout(out):
+            bot_cli.cmd_set_pin(argparse.Namespace(link="https://chat.whatsapp.com/abc"))
+        text = out.getvalue()
+        self.assertIn("f_username=f_user_42", text)
+        self.assertIn("t_username=t_user_42", text)
+        mock_hal.set_security_pin_api.assert_called_once_with("https://chat.whatsapp.com/abc")
+
+    @mock.patch.object(bot_cli, "CM_BOT_HAL")
+    def test_falsy_set_security_pin_result_exits_nonzero(self, mock_hal_class):
+        mock_hal = mock_hal_class.return_value
+        mock_hal.is_whatsapp_url.return_value = True
+        mock_hal.get_whatsapp_link_username.return_value = ("t", "f")
+        mock_hal.set_security_pin_api.return_value = False
+        with self.assertRaises(SystemExit) as cm:
+            bot_cli.cmd_set_pin(argparse.Namespace(link="https://chat.whatsapp.com/abc"))
+        self.assertEqual(cm.exception.code, 1)
+
+    def test_set_pin_subparser_dispatches(self):
+        parser = bot_cli.build_parser()
+        args = parser.parse_args(["set-pin", "https://chat.whatsapp.com/abc"])
+        self.assertIs(args.func, bot_cli.cmd_set_pin)
+        self.assertEqual(args.link, "https://chat.whatsapp.com/abc")
+
+
 if __name__ == "__main__":
     unittest.main()