"System" items currently consist of a pair of zabbix-agent-test items.

README.txt

 /etc/zabbix_agentd.conf must include the line:
   Include=/usr/lib/zabbix/agent-configuration
 
+For SUDO functionality needed with some keys, 
+  # Allow Zabbix to run any command in the authorized directory
+  Defaults:zabbix !requiretty
+  zabbix ALL=(root:operator) NOPASSWD: /usr/local/lib/zabbix/bin/
+
 See https://git.uibk.ac.at/zid-scripts/zabbix/wikis/home

agent-configuration/system

+#=== ZABBIX HELPER SCRIPTS (UserParameters) ===
+# vim: ft=conf:sw=2:sts=4:expandtab:
+# Author: Otheus.UIBK@gmail.com
+# Date: 2015-03-09
+#
+#--- System extensions ---
+# 
+#  system.test_trigger[<dir-path>]
+#
+#  If <path> exists and is not empty, return contents. Otherwise ZBX_ERROR
+UserParameter=system.test_trigger[*],f="$1";test -s "$f" -a -r "$f" && head -n1 "$f" || echo ""
+UserParameter=system.test_trigger_random[*],echo $[ $RANDOM % 2 ]