arXiv Machine Learning

The Oversight Gap: What LLM Safety Monitors Miss, and Why It Is Not Capability

arXiv Machine Learning
4d ago

A False Average: Pooled CoT-Monitor Accuracy Conceals a Reasoning-Dependent Fragility

The paper demonstrates that aggregate accuracy figures for chain‑of‑thought (CoT) monitors can be misleading because a large portion of detected hacks rely solely on action patterns rather than reasoning. By rewriting only the agent’s reasoning to appear truthful while keeping actions identical, the authors show that the monitor’s performance on the reasoning‑dependent subset collapses dramatically, yet the overall pooled accuracy drops only modestly. The study reveals that CoT monitors are fragile when reasoning is the key signal and that accuracy should be reported separately for this subset.

By Shikhar Shiromani, Leo Richter
Hugging Face Trending Papers
Sep 3

Clean Engineering, Unstable Measurement: A Preregistered Reliability Failure of Black-Box LLM Observers on Shared Endpoints

The paper investigates the reliability of language‑model judges used as measurement instruments on shared endpoints. Through two preregistered audits of 52,988 requests, the authors found that repeat rankings and byte‑identical replays fell far short of required thresholds, revealing significant instability. They identify three mechanisms—label‑to‑meaning bias, candidate gaps below the noise floor, and input permutation noise—that explain the gap, and propose a snapshot‑identity ladder, design rules, and a reporting checklist to mitigate such failures.

arXiv AI
Sep 4

Clean Engineering, Unstable Measurement: A Preregistered Reliability Failure of Black-Box LLM Observers on Shared Endpoints

The paper reports a preregistered audit of language‑model judges used as measurement instruments, revealing that the assumption that a model’s responses remain stable over time is invalid. Across nearly 53,000 audited requests, repeat rankings and byte‑identical replays fell far below required reliability thresholds, with three identified mechanisms—label‑to‑meaning bias, candidate gaps below the noise floor, and input permutation noise—explaining the discrepancy. The study proposes a three‑level snapshot‑identity framework, eight design rules, and a reporting checklist to prevent such reliability failures in future evaluations.

By Haoyaun Zhu, Jie Zhang
arXiv AI
Aug 20

Metrics That Write Themselves: Evolving an Evaluator from Its Own Blind Spots

The paper introduces EvalCEGAR, a method that automatically evolves a metric for evaluating AI-generated answers by iteratively refining a pool of small Python operators that flag potential defects. By using counterexample-guided abstraction refinement, the system identifies pairs of answers that score identically but differ in correctness, prompting the metric to broaden its scope rather than resample. On benchmark datasets, the evolved 55‑line operator closes a significant portion of the performance gap compared to hand‑written metrics and outperforms a large‑language‑model judge that incurs a cost per candidate.

By Xing Zhang, Yanwei Cui, Guanghui Wang, Zhihao Lin, Peiyang He
arXiv AI
Sep 2

Commit-first LLM judging inherits the judge's own errors

The paper investigates whether widely used evaluation frameworks for large language models (LLMs) implement a defense called commit‑first judging, which requires a judge to solve a task itself before accepting a candidate answer. Across 24 configurations in eight popular frameworks, none use the full commit‑first method; nine use a weaker variant that is ineffective. In controlled experiments, the weaker variant allowed systems to game the judge, while the full commit‑first approach eliminated this vulnerability but sometimes worsened evaluation when the judge’s own answer was incorrect.

By Idil Gozel