An agent memory framework modelled on hippocampal replay learned from comparing its own attempts and improved on three agent benchmarks
AspireAI community · arXiv (cs.AI)
Hippo lets LLM agents improve without touching model parameters by comparing attempts at the same task to identify reusable decisions and refining them when shortcomings are diagnosed. The stored experience is compared against existing memory so overlaps merge and conflicts resolve through explicit applicability conditions, which means prior guidance can be revised without keeping every lesson as a separate entry. Experiments on SWE-bench Verified, WebArena and Mind2Web show performance gains in all three settings and substantially fewer retained experiences than an accumulation baseline - a baseline that initially improves but eventually performs below a no-memory baseline. The gains held across base models of varying capability. The limitation: the method assumes the agent gets repeated attempts at a task it has already seen.
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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.