Agent memory scores measured on a fixed snapshot stop meaning much as the memory grows
AspireAI community · arXiv (NeurIPS 2026)
Memory-agent evaluations report fixed-snapshot accuracy or retrieval quality, but those numbers do not show whether stored evidence is still usable once irrelevant sessions pile up. This paper proposes a scale-conditioned protocol that holds task evidence fixed while adding irrelevant sessions, and reports four diagnostics including budget-compliant reliability and the usable-scale boundary where reliability falls below target. On LongMemEval, HippoRAG stays inside its two-call budget but loses 16-20 percentage points of budget-compliant reliability as irrelevant sessions accumulate, and LiCoMemory's failures depend strongly on which agent drives it, with Qwen3-8B exceeding the budget while Qwen3-32B and Qwen3-235B stay reliable in the tested range. The practical consequence is that scalable-memory claims need to be stated conditionally on agent, interface, scale range and interaction budget.
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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.