diff --git a/tox.ini b/tox.ini
index 5a890cf..2b2b23e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -64,6 +64,10 @@ extras =
   docs
 commands =
   sphinx-build -j auto -W -T --keep-going -b html {posargs} {toxinidir}/docs/ {toxinidir}/docs/_build/html
+passenv =
+  CI
+  GITHUB_BASE_REF
+  GITHUB_REF_NAME
 
 [testenv:docs-clean]
 skip_install = true