Icinga2/Director, how do I change the status (OK, Warning, Critical) of a service based on a custom command sent via Icinga Agent?

Question

Having trouble figuring this out, new to icinga, but want to be able to set up custom commands that get ran via Icinga Agent on the remote host, and have the state change based on the result. Like passing uptime to a host, and going critical if its below a certain time, or passing a ps aux | egrep cron and going critical if the amount of processes is above or below a certain number. I have the custom commands set up, and executing via the agent just fine, but I don't know how to dictate the state based on the result. Can someone point me in the right direction?