At the moment, there doesn't seem to be any way to, for example, specify a test plan from the command line. All of these parameters should be passable from the command line, even if you have some generic --set-field command line argument. This is especially useful if there are a large number of CRs I need to submit (for example, I'm CR'ing a patchset with many patches in it.)

The plumbing does seem to allow specifying this manually, but I may still want the interactive interface, e.g. to edit the commit message myself and run lint, so using the interface directly seems suboptimal.