diff --git a/setup.cfg b/setup.cfg
index e520aaf56d6..1b5a566a520 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -39,6 +39,7 @@ install_requires =
     gfal2-python
     M2Crypto >=0.36
     pexpect
+    prompt-toolkit >=3
     psutil
     pyasn1
     pyasn1-modules