diff --git a/artiq/frontend/artiq_rpctool.py b/artiq/frontend/artiq_rpctool.py
index b9b302fd4..bdecadb89 100755
--- a/artiq/frontend/artiq_rpctool.py
+++ b/artiq/frontend/artiq_rpctool.py
@@ -3,7 +3,7 @@
 import argparse
 import textwrap
 import sys
-import numpy as np
+import numpy as np  # Needed to use numpy in RPC call arguments on cmd line
 
 from artiq.protocols.pc_rpc import Client
 
diff --git a/doc/manual/utilities.rst b/doc/manual/utilities.rst
index 97742192b..212180a23 100644
--- a/doc/manual/utilities.rst
+++ b/doc/manual/utilities.rst
@@ -61,10 +61,11 @@ in order to call remote functions of an ARTIQ controller.
             $ artiq_rpctool.py hostname port call -t target f x1 x2 ... xN
 
         You can use Python syntax to compute arguments as they will be passed
-        to the ``eval()`` primitive. But beware to use quotes to separate
-        arguments which use spaces::
+        to the ``eval()`` primitive. The numpy package is available in the namespace
+        as ``np``. Beware to use quotes to separate arguments which use spaces::
 
             $ artiq_rpctool.py hostname port call -t target f '3 * 4 + 2' True '[1, 2]'
+            $ artiq_rpctool.py ::1 3256 call load_sample_values 'np.array([1.0, 2.0], dtype=float)'
 
         If the called function has a return value, it will get printed to
         the standard output if the value is not None like in the standard