Web world models were 86.1 percent plausible and still made the wrong authorisation calls
AspireAI community · arXiv
Web world models predict the consequences of candidate actions before an agent acts, and a plausible predicted future does not automatically support the correct safety decision. In a matched human evaluation of 3,000 predictions from ten frozen open models, 86.1 percent were judged semantically plausible, yet several models showed highly asymmetric authorisation behaviour, combining low false-safe execution with poor recall of clarifiable ASK cases and a strong preference for BLOCK. That motivates safety sufficiency: whether a predictive interface preserves and exposes the policy-decisive information needed to tell EXECUTE from ASK from BLOCK. SafeWebWorld benchmarks that across five web-safety domains. Under a controlled security-aligned fine-tuning protocol, evidence preservation improved substantially while authorisation-sensitive decisions deteriorated, and latent authorisation recovery showed recovery was substantial but backbone-dependent.
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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.