Newsletters Won’t Rank Themselves. Someone Just Solved That With a Rubric

Five layers of injection defense guard a pipeline that reads your inbox for you.

u/pablooliva just shared the writeup for a daily news-scoring system built to take a pile of newsletters and hand you a single ranked digest. Not another “AI summarizes your email” toy. A real scoring pipeline that had to survive contact with reality.

Here’s the twist. The hard part wasn’t the summarizing. It was getting the model to actually rank things. Left alone, a scoring model parks every item at 6.5 and calls it a day. Useless for sorting anything. The fix was a rubric with worked examples, an 8 looks like this, a 2 looks like that, plus explicit “deprioritize” flags for funding announcements with no product angle, job listings, conference promos. That’s the difference between a model that scores and a model that judges.

The second problem is nastier. Every newsletter that lands in this pipeline is attacker-controlled content. Anyone can email it. So five layers of prompt injection defense sit between the inbox and the model, and every single response gets schema-validated before it’s trusted.

Mini-workflow if you’re building anything similar 🛠️:

  1. Write the rubric before you write the pipeline. Worked examples of high and low scores beat any instruction like “score 1-10.”
  2. Add explicit deprioritize categories. Tell the model what garbage looks like, not just what good looks like.
  3. Treat every external input as hostile. Email, RSS, scraped pages, all of it.
  4. Schema-validate every model response before it touches your pipeline. No exceptions.
  5. Layer your injection defenses. One filter is a suggestion. Five is a wall. 🧱

Pro tip: if your scores all cluster near the middle, that’s not a data problem, that’s a missing rubric. Fix the prompt before you touch the data 💡.

Grab the writeup, steal the rubric trick, and go make your own scoring pipeline actually rank something 🚀

N Newsletters to 1 Digest, Built for AI Engineers
by u/pablooliva in PromptEngineering

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