diff --git a/pyproject.toml b/pyproject.toml
index 9f2a26b..30d29dd 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -74,6 +74,7 @@ optional = true
 [tool.setuptools_scm]
 
 [tool.cibuildwheel]
+environment-pass = ["RUNNER_OS"]
 test-groups = ["dev"]
 test-command = [
     'python -c "import mwparserfromhell.parser._tokenizer"',