diff --git a/pyproject.toml b/pyproject.toml
index 63d17ab66b..bb554a26b7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,7 +21,7 @@ quote-style = 'single'
 
 [tool.ruff.lint]
 ignore = ['E402', 'E722', 'E741', 'E401']
-select = ['E', 'F', 'I', 'W']
+select = ['E', 'F', 'I', 'W', 'INT']
 
 [tool.ruff.lint.per-file-ignores]
 "src/calibre/ebooks/unihandecode/*codepoints.py" = ['E501', 'W191']