diff --git a/src/tox.ini b/src/tox.ini
index 628b390..0e36e84 100644
--- a/src/tox.ini
+++ b/src/tox.ini
@@ -10,7 +10,7 @@ setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
          AMULET_SETUP_TIMEOUT=5400
 whitelist_externals = juju
-passenv = HOME TERM AMULET_* CS_API_*
+passenv = HOME TERM AMULET_* CS_*
 deps = -r{toxinidir}/test-requirements.txt
 install_command =
   pip install {opts} {packages}