diff --git a/worldbuild-runner.py b/worldbuild-runner.py
index 30733d1..5180d9f 100755
--- a/worldbuild-runner.py
+++ b/worldbuild-runner.py
@@ -20,6 +20,7 @@ from subprocess import Popen
 from signal import SIGINT
 import threading
 import re
+import sys
 
 prefix = ""