diff --git a/tox.ini b/tox.ini
index 28cfcd8..babf033 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,14 +4,10 @@ minversion = 3.5
 # hack to prevent .tox from crapping to the project directory
 toxworkdir={env:TOXWORKDIR_BASE:}{toxinidir}/.tox
 
-[testenv]
-passenv = 
 # useful for tests to know they are running under ci
-  CI
-  CI_*
 # respect user's cache dirs to prevent tox from crapping into project dir
-  MYPY_CACHE_DIR
-  PYTHONPYCACHEPREFIX
+[testenv]
+passenv = CI,CI_*,MYPY_CACHE_DIR,PYTHONPYCACHEPREFIX
 
 
 # just the very core tests with minimal dependencies