EvoIn: Bridging Evolution and Internalization for Agent Fine-Tuning
AspireAI community · arXiv
EvoIn improves agents by changing how they decide rather than by piling on tools. It reads execution traces, evolves and validates new decision-making procedures by temporarily instantiating them in the harness, then rewrites the resulting reasoning traces into self-contained form with no reference to harness instructions before fine-tuning the model on them. The authors report that this raises agent pass rate by 10.9 points in-domain and by 9.2 points out-of-domain, that the internalized procedures generalize to unseen tasks, and that the approach also works on another model family. Their case studies show an agent learning to decide how to solve a task before solving it, for example by checking a document's length to choose between reading it in full and searching it. The v2 revision left the results unchanged.
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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.