The project is small and a few things will go a long way to doing it just right so a couple optional joinery comments if you want to make it a little better.
-Use a proper timber splice joint at the plates. And to emphasize what Dave said, the best and strongest place to position the splice is not over the post.
-Don't hold the posts together with pegs. Use a wedged, half dove tail with the tie beams for this job.
-Use timber size rafters ideally with step-lapped seats.
-Since you only need a small quantity, note good pegs can also be made with just a chisel.
