There are a few ways we could go about this:

1: It Just Works™

I think @mislav has more concrete thoughts on this direction! This could be really delightful and easy but my concern here is blocking behavior for anyone who doesn't want this behavior, or it being too quick and leaving people confused at what just happened

2: Flag + Survey

I think we could include a flag for this and a survey prompt like we do for title and body:

~/Projects/my-project$ gh pr create 

Creating pull request for [branch] into [master]

? Repository 
> desktop/desktop
  ampinsk/desktop
? Title Title
? Body (nano) <Received>
? Submit? 
> yes
  edit
  cancel

https://github.com/desktop/desktop/pulls/4

Plus add a flag (language WIP):

-r, --repo    The repository you want your pull request opened in

@olgabot also left a great comment here outlining how she'd expect it to work: https://github.com/github/homebrew-gh/issues/6#issuecomment-566622632

Curious to hear thoughts!

Ref: https://github.com/github/homebrew-gh/issues/6