Fragile novelty judgments and the limited payoff of personalized skills

Agents in Practice #19 on how prompt wording flips LLM judgments of research novelty, and personalized skills failing to outperform a generic skill for coding agents.
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Author

Ryan Lee

Published

November 13, 2026

Welcome to the 19th issue of Agents in Practice.

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How reliably can LLMs judge novelty?

How AI models judged novelty

Researchers from Ai2 and the Hebrew University of Jerusalem studied whether LLMs can reliably judge the novelty of research ideas. The authors used peer reviews to identify human-authored ideas with strong agreement about their novelty. They tested six models on ideas from ICLR 2026 papers and ideas generated by LLMs, varying the prompts, reasoning budget, and access to related papers.

The researchers found that models are susceptible to how the model is prompted to judge novelty. Given a human-authored-and-reviewed idea and a generated idea, GPT-5.4 preferred the human idea 93.5% of the time when it was told reviewers had found one idea novel and the other not. However, asking only which idea was novel lowered this to 40.9%, changing its verdict on more than half of the same pairs. Prompt changes also flipped roughly a quarter to a third of verdicts when comparing ideas from two AI generators.

The authors also write that providing related papers or more reasoning did not consistently improve judgments.

Personal Thoughts

Novelty is such a difficult concept to evaluate. Even human reviewers often disagree whether a paper is sufficiently novel, especially when the outcome seems “obvious” in retrospect. Using ICLR reviews seems like a nice way to proxy human perception of novelty, but I wonder how much of this will be contaminated by reviewers using LLMs.

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Do personalized skills help coding agents?

How recurring developer preferences are distilled

Researchers from UMass Amherst and OpenRefinery.ai studied whether coding agents benefit from skills that capture a developer’s preferences. Their method used pattern matching to build an initial skill file, then an LLM to refine it, keeping rules supported by at least two separate sessions. They replayed tasks with an LLM simulating developer follow-ups and another LLM scoring completion. Only one of the eight model pairings showed a statistically significant improvement in task scores with personalized skills.

In a separate comparison using one model setup, a generic skill built from multiple developers’ conversations raised average task scores by 3.11 points out of 100 compared with using no skill (65.27 → 68.38). However, the difference between generic (68.38) and personalized (67.64) skills was not statistically significant. Skills also did not consistently reduce follow-up requests from the simulated developer.

Personal Thoughts

This is a continuation of my anecdote from two weeks ago. It seems like building personalized skills often leads to local optima and becomes a maintenance burden. Yet, in some areas personalization is still important. Keeping personalization lightweight yet consistent across different LLMs seems like an interesting problem, both for researchers and product engineers.

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