arXiv Machine Learning

Calibration-Family Overfit: Why Trusted Sabotage Monitors Don't Transfer Across Lineages

arXiv:2607. 06596v1 Announce Type: cross Abstract: Trusted monitoring is a central defense in AI control: a cheaper trusted model scores an untrusted model's actions for sabotage, and the most suspicious are audited or deferred.

arXiv AI
Aug 26

More Rejective, Not More Discriminative: The Unit of Verification in Pre-Execution LLM Oversight

The paper introduces the twin‑prefix framework to evaluate how the size of the verification unit—i.e., how many actions a pre‑execution LLM monitor reviews in one call—affects its performance. By pairing each gold plan with a twin that differs by a single write and injecting a controlled error, the authors isolate the impact of review length on catch rates and false rejections. Their findings show that longer review windows increase rejection rates but do not improve discrimination, with the highest informedness occurring at one or two actions across all judges and domains.

By Yuchen Han, Cheng Yan, Wuyang Zhang
arXiv Machine Learning
Sep 14

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
arXiv AI
Sep 7

Harness-agnostic detection and immunization of reward hacking in self-evolving language models

The paper introduces HackProbe, a black‑box monitoring tool that can be attached to any self‑evolving language model loop without accessing internal weights or activations. HackProbe uses a fixed‑distribution comparison core and a rotated fresh layer to detect reward hacking through four statistical tests, and it can immunize the model by selecting honest candidates from the proposal pool. Experiments on a controlled host with injected hacking channels show that HackProbe achieves higher AUROC and lower false‑positive rates than the strongest baseline, and its bandwidth‑limited reselection improves true capability under hacking more than it harms clean runs.

By Rongxin Yang, Yang Liu, Shang Luo, Haoxuan Jia, Chongyang Zhang, Hao Zheng, Yingguang Yang, Yulin Huang, Jianshen Zhang, Yongzhi Qi, Kefu Xu, Congjing Ran, Bin Chong
arXiv AI
Sep 10

Protocol effects on feature-based hardware-Trojan detection across Trust-Hub families

The study evaluates how the choice of test boundary affects feature‑based hardware Trojan detection across Trust‑Hub families. Using a corpus of 49,124 gates from 16 netlists, the authors compare three test settings—pooled gates, a single netlist held out, and an entire host family held out—showing that performance drops markedly when a host family is excluded. The results demonstrate that sibling benchmark variants can inflate detection metrics, and the authors recommend reporting family‑aware holdouts alongside pooled scores.

By Hang Xiao, Chuhong Xu, Kainan Zhou, Gangzhen Qian, Lu Yi