diff --git a/build/ci/jenkins/NightlyCI.groovy b/build/ci/jenkins/NightlyCI.groovy
index b1b8ef39cacaef9e79c75830d8705309bbcbeb4d..10e4d6b304222f4ab18118b09ed77fce3c249316 100644
--- a/build/ci/jenkins/NightlyCI.groovy
+++ b/build/ci/jenkins/NightlyCI.groovy
@@ -1,5 +1,7 @@
 #!/usr/bin/env groovy
 
+// When scheduling a job that gets automatically triggered by changes,
+// you need to include a [cronjob] tag within the commit message.
 String cron_timezone = "TZ=Asia/Shanghai"
 String cron_string = BRANCH_NAME == "master" ? "50 20,22,0,6,11,16 * * * " : ""