Caper approves coding-agent commands by running them in a snapshot first, and cut harmful outcomes to 6.7 percent
AspireAI community · arXiv (cs.CR, cs.AI)
Automated approvers that decide whether a proposed shell command may run typically judge the text of the request and the command. Caper instead pre-executes each command in a snapshotted sandbox, gives an independent approver a bounded report of the effects it observed, then commits allowed commands and rolls back blocked ones with a reason the agent can act on. Against six existing systems, Caper reports the lowest harmful-outcome rate on SABER at 6.7 percent versus at least 14.8 percent, and on YoloFS-Ext, a benchmark the authors built where the harmful behaviour is hidden inside invoked tools, 7.8 percent versus at least 35.3 percent, while blocking 1.0 percent of the safe twins of the dangerous tasks. The trade-off is latency: the command has to run before it is allowed.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.