Set selected radio button from context

Hello, as far as I know it is possible to get the default value of a text field from the context as follows:

[text* your-name default:get “Your Name”]

How can I do the same for radio buttons? I would like to have a radio button set by default to the second option, unless there’s a specific value on the querystring (?newsletter=Agree). What do I have to add to get the value from the querystring but keep the fallback to 2 when no values is passed by the url?

[radio newsletter default:2 “Agree” “Do not agree”]