A structured verify-and-backtrack loop beat reflection-style recovery by up to 22 points on AppWorld
AspireAI community · arXiv (cs.AI)
The hard part of long-horizon agent tasks is not trajectory length but recovery when a prerequisite is missing or an earlier decomposition failed. The Verify-Backtrack Loop is a training-free extension of ReAct that keeps the task decomposition as a bounded goal stack and, on goal activation, execution failure or material state change, jointly verifies two horizons: whether the active goal contributes to the terminal goal, and whether it is feasible in the current state. Those dual-horizon judgments plus typed failure attribution drive explicit Push, Pop, retry and BacktrackTo operations. Evaluated on AppWorld, ALFWorld and ScienceWorld with Qwen3.5-9B, GPT-4o and DeepSeek-V3.2, the loop improves over ReAct and reflection-based control on every backbone-benchmark pair, by up to 22.07 percentage points on AppWorld. Ablations show that removing either verification or diagnosis drops performance, in several settings below plain ReAct, confirming the two mechanisms are complementary.
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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.