The user is staring at a wall of text and wants the point. Give a tight summary — nothing they have to wade through.
- Target: by default, your own previous message. If the user pointed at something else — a file, a doc, pasted text — summarize that instead.
- Length: a few bullets or a couple of sentences. If it's longer than what someone reads in ~15 seconds, it's still too long.
- Keep the decisions, the answers, and the actions the user needs. Cut the reasoning, caveats, background, and restatement.
- No meta: don't announce that you're summarizing or apologize for the length. Just deliver the short version.