Yeah some instruction to be as concise as possible would help, and on the comments summary an instruction to not discuss hacker news or that it’s comments.

Congrats on a great idea well executed!

In my mind, the gold standard for engaging summaries is Seeking Alpha. As a random example, see https://seekingalpha.com/article/4633758-sell-amazon-before-...

If you could train the model to come up with well structured bullet points, the summaries would be amenable to scanning before committing to fully engage. This is just an idea, I am not sure what fraction of your readers would prefer bullet points.