alt Hacker NewsWork doesn't start with a PR description though. I'm assuming most people that are using LLMs start with some sort of document (plan, spec, intent, etc) which captures intent.
I guess you could also use all the session rollouts saved to disk that were related to that task, and distill them somehow.
Writing a paper doesn't start with writing an abstract too, but no one wants to get hit with all the notes that a scientist has collected on his experiments. The abstract is a nice 10-30 seconds explanation on why this paper is worth reading.
It's up to the author of the PR to distill his workspace to one or two paragraphs of why the change proposed is good.