Read about code fences… the easiest is 3 ticks before and after the code or log.
I’ll take a look later this afternoon.
I thought I had figured this out, but ended up having to look into the code to figure it out. This worked for me, and is the same format in Jython, Groovy, etc., minus the semicolon.
actions.get("mqtt", "mqtt:systemBroker:embedded-mqtt-broker").publishMQTT("test/system/started", "true");