how to document implicit (path?) parameters that are in the url path

It wasn't immediately clear to me what syntax I would use to document examples and other info for an implicit parameter defined by a symbol in the URL path, e.g.

        desc 'return a specific check', {
          headers: SWAGGER_HEADERS,
        }
        get '/:id' do

as opposed to

        desc 'return a specific check', {
          headers: SWAGGER_HEADERS,
        }
        params do
          requires :id, type: String, documentation: { example: '7', desc: 'Unique Identifier' }
        end
        get '/' do

i tried:

 get '/:id', documentation: { example: '7', desc: 'Unique Identifier' } do

but that didn't seem to work ... at least the presence of a path parameter generates a little chunk of swagger liks this:

          {
            "in": "path",
            "name": "id",
            "type": "integer",
            "format": "int32",
            "required": true
          }

but I was wondering if there was some syntax to add an example and/or desc to this ...

Start with the issue's two Grape route examples and the generated Swagger path-parameter output. Check the project's documentation and parameter-handling entry points for existing syntax covering implicit URL parameters, then verify whether an example and description can be represented. Done means documenting the supported syntax or clarifying that it is not supported.