The MAUI team has a good example of this:

We have added the "s/needs-repro" label to this issue, which indicates that we require steps and sample code to reproduce the issue before we can take further action. Please try to create a minimal sample project/solution or code samples which reproduce the issue, ideally as a GitHub repo that we can clone. See more details about creating repros here: https://github.com/dotnet/maui/blob/main/.github/repro.md

This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

I think they have some automation to add that message to any issues that get the needs-repro label added as well, which would be extra fancy.

To start with, we could at least add some docs that we could easily refer to when asking people for a reproduction of the issue.