I love this idea. I agree that the majority of the time Graphite should surface positive messages. As of now, it's technically pretty neutral phrasing, but it lands for many people as not neutral, especially if they're insecure for any reason (new hire, having a hard time, etc)
One framing I've found helpful interpersonally (and it applies here too) is to phrase things in ways where you aren't talking about the person. So instead of "You reviewed more PRs than average this week", something like "This was a lighter week than usual". It's about the week, not about the person.
This is actually more accurate too! Maybe you had a bunch of meetings that week, or an offsite, or had to sit on hiring panels, or your tasks were smaller/bigger, or you were sick, or religious holidays, or Github was down so nobody got things done, or, or, or... Most of the time, these fluctuations aren't due to the person, they're due to the circumstances the person finds themselves in.
So some sample copy from me (not a copy editor)
⢠𪶠It was a lighter week than usual
⢠š„ Wow, what a week for merging!
⢠š Hey Sherlock, this was a big week for reviews!
⢠āļø Wow so much, very code!