diff --git a/tests/tools/test_send_message_tool.py b/tests/tools/test_send_message_tool.py
index d55998942..b5cb33200 100644
--- a/tests/tools/test_send_message_tool.py
+++ b/tests/tools/test_send_message_tool.py
@@ -25,8 +25,11 @@ def _make_config():
 
 
 def _install_telegram_mock(monkeypatch, bot):
-    telegram_mod = SimpleNamespace(Bot=lambda token: bot)
+    parse_mode = SimpleNamespace(MARKDOWN_V2="MarkdownV2")
+    constants_mod = SimpleNamespace(ParseMode=parse_mode)
+    telegram_mod = SimpleNamespace(Bot=lambda token: bot, constants=constants_mod)
     monkeypatch.setitem(sys.modules, "telegram", telegram_mod)
+    monkeypatch.setitem(sys.modules, "telegram.constants", constants_mod)
 
 
 class TestSendMessageTool: