-a-

(define-method
  (account/info
    (path (cut string-append "hello-" <>))
    pos-arg-2
    #!key
    (key-arg-1 (cut string-append "hi-" <>))
    key-arg-2
    (key-arg-3 "default"))
  "http://example.net/"
  #f
  read-json)

-b-

(define-method
  (account/info
    (path (cut string-append "hello-" <>))
    pos-arg-2
    #!key
    (key-arg-1 (cut string-append "hi-" <>))
    key-arg-2
    key-arg-3)
  "http://example.net/?key-arg-3=default"
  #f
  read-json)