R Plumber API - programmatically specify JSON schema for request

I'm trying to build a plumber API in R. Have started with this example from the docs...

pr() %>%
  pr_post("/echo", function(req, res) {
    if (is.null(req$body)) return("No input")
    list(
      input = req$body
    )
  }) %>%
  pr_run(port = 8080)

API starts OK. However, I want my handler function to use JSON in the body of the request as inputs.

Is it possible to programmatically define a JSON schema such that it's populated as the example in the swagger docs for the API?

Thanks.

Looks like this post Plumber: getting request body/schema in UI has the solution.

This is (unless anyone can tell me it's bad practice) the example I was looking for...

v <- data.frame(a = c(2, 3), 
                b = c(3, 4))

pr() %>%
  pr_post("/add_up", function(input = v) {
    input <- input[[1]]
    return(list(rowSums(input)))
  }) %>%
  pr_run(port = 8080) 

This gives the following example JSON in the swagger docs...

{
  "input": [
    [
      {
        "a": 2,
        "b": 3
      },
      {
        "a": 3,
        "b": 4
      }
    ]
  ]
}

...and returns the following response...

[
  [
    5,
    7
  ]
]

Can anyone offer any improvement? Might be nice to remove the 'input' from the JSON schema if possible.