content: 
  tell application "Keynote"
      set out to "["
      repeat with i from 1 to the count of documents
          set fil to file of document i
          set rec to "{" & ¬
              "\"id\": \"" & id of document i & "\", " & ¬
              "\"filename\": \"" & POSIX path of fil as text & "\"" & ¬
              "}"
          if i > 1 then
              set out to out & ", "
          end if
          set out to out & rec
      end repeat
      set out to out & "]"
      out
  end tell
  