diff --git a/tox.ini b/tox.ini
index 7dacb45..cef4c06 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,7 +23,7 @@ commands =
 [testenv:functional]
 commands =
     coverage run -m pytest --capture=no --strict {posargs}
-    coverage report -m --omit="*/test*"
+    coverage report -m --omit="*/test*" --fail-under=99
 
 # environment used by the -infra templated docs job
 [testenv:venv]