The Entanglement Wall: Activation-Space Probes as Risk Detectors, Not Context Adjudicators

arXiv:2607.13075 · cs.CR, cs.AI, cs.LG · Submitted 2026-07-12 · Read on arXiv

cs.CR, cs.AI, cs.LG

Submitted: 2026-07-12

Updated: 2026-09-27

Comments: 19 pages, 4 figures, 30 tables. Code and supporting artifacts: https://github.com/dschwarz32/entanglement-wall

Code: https://github.com/dschwarz32/entanglement-wall

License: http://creativecommons.org/licenses/by/4.0/

The gist: Context can change whether a request is harmful without changing its topic or surface form.

Terminology

Abstract

Context can change whether a request is harmful without changing its topic or surface form. We ask whether residual-stream probes distinguish harmful requests from surface-matched benign controls at a useful operating point. Across three 7-8B model families, an activation sensor blocks 95.5-97.7 percent of judge-classified compliant attacks in a taxonomy-selected set. It also blocks 59.6-68.4 percent of XSTest prompts. A fully disjoint audit reconstructs near-ceiling source-contrast AUROC (0.996-0.999), but fixed transfer to matched pairs is weaker: 0.656-0.819 on the guard-selected Twin-n70 subset and 0.590-0.690 on the full Twin-n163 cohort. We test ten axes on the reference family and seven across all families with leakage, hold-out, and permutation controls. On Twin-n163, no axis evaluated without direct pair-boundary fitting reaches the specified numerical threshold. Requiring persistence on that full cohort was added at analysis time. A separately specified 24B/32B extension gives the same result. Pair-trained classifiers weaken under category and generation-batch hold-out and false-block 79.6-100 percent of XSTest at 95 percent in-corpus TPR. At the tested read points, these activation scores behave as broad-risk detectors rather than standalone context adjudicators.

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