access controller instance variables in representers

[tamoyal]

I see in the documentation that we should be able to access instance variables in the rabl however it does not work for me.

def create_thing
   @stuff = {key: "value"}
    render json: Rabl.render(@thing, "thing")
end

In the representer, accessing @stuff does not work:

node(:stuff) do
   @stuff[:key]
end

Passing around locals due but I'm trying to access the Rails request context in my rabl representers. Any idea why this wouldn't work or am I misunderstanding the docs?