That’s a good catch 
- wrapping in [event]...[/event] is definitely the way to get things showing nicely in the calendar UI.
Just to note: the variant under the details pane “with discourse-calendar compatibility” in my earlier post already does exactly this, so anyone who wants native event rendering can copy that block as-is.
Still, it’s helpful seeing it written out again here - makes it clearer what part of the body builder to tweak. If you’ve got any further refinements (extra attributes, or handling for all-day vs timed events), do share them - I think others following along would benefit.