diff --git a/artiq/frontend/artiq_rpctool.py b/artiq/frontend/artiq_rpctool.py
index 876abb978..b9b302fd4 100755
--- a/artiq/frontend/artiq_rpctool.py
+++ b/artiq/frontend/artiq_rpctool.py
@@ -3,6 +3,7 @@
 import argparse
 import textwrap
 import sys
+import numpy as np
 
 from artiq.protocols.pc_rpc import Client