Observational world models make a predictable mistake when the agent's own actions change what happens next
AspireAI community · arXiv
Modular LLM agents plan across components whose actions causally change downstream state, so an agent has to predict not just what happens next but what happens because of what it did. The authors show that purely observational world models carry irreducible intervention-time error in these systems even when they model observational trajectories accurately. CausalCompose is a causal world-model framework that adds causal structure for intervention-aware prediction and planning, and the paper proves that causal composition can close that gap given sufficient evidence and controlled local error. Experiments across modular agent environments show consistent gains in intervention-sensitive reasoning and planning, with the clearest improvements in structured tool-use systems where causal dependencies directly govern execution. The honest boundary is stated in the result itself: causal world models help when causal dependencies are both identifiable and actionable for planning. In systems where those dependencies cannot be pinned down, the framework has less to offer.
Read the story and explore more from the AspireAI community.
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.