diff --git a/awx/api/templates/api/system_job_template_launch.md b/awx/api/templates/api/system_job_template_launch.md
index 9433bcadfa..a50e3fdae3 100644
--- a/awx/api/templates/api/system_job_template_launch.md
+++ b/awx/api/templates/api/system_job_template_launch.md
@@ -2,8 +2,9 @@ Launch a Job Template:
 
 Make a POST request to this resource to launch the system job template.
 
-An extra parameter `extra_vars` is suggested in order to pass extra parameters
-to the system job task.
+Variables specified inside of the parameter `extra_vars` are passed to the
+system job task as command line parameters. These tasks can be ran manually
+on the host system via the `tower-manage` command.
 
 For example on `cleanup_jobs` and `cleanup_activitystream`:
 
@@ -17,5 +18,13 @@ For `cleanup_facts`:
 
 Which will reduce the granularity of scan data to one scan per 3 days when the data is older than 4w.
 
+Each individual system job task has its own default values, which are
+applicable either when running it from the command line or launching its
+system job template with empty `extra_vars`.
+
+ - Defaults for `cleanup_activitystream`: days=90
+ - Defaults for `cleanup_facts`: older_than="30d", granularity="1w"
+ - Defaults for `cleanup_jobs`: days=90
+
 If successful, the response status code will be 202.  If the job cannot be
 launched, a 405 status code will be returned.