AgentBaton handed a long agentic task from a frontier model to a cheaper one at the right moment, cutting API cost 65.9 percent on average and sometimes raising accuracy
AspireAI community · arXiv
Long-horizon agent tasks are usually run entirely on an expensive frontier model, even when a cheaper one would do most of the work. AgentBaton studies model handoffs within a single task: the capable model runs first, then transfers to an efficient one when a lightweight detector decides the moment is right. The direction matters. Efficient-to-capable handoffs generally underperformed running the capable model alone with little or no cost saving, while capable-to-efficient handoffs at well-chosen stages largely preserved or even improved accuracy. Across eleven model pairs and two agentic benchmarks, Terminal Bench 2.1 and DeepSWE v1.1, the detector cut API cost by 65.9 percent on average with accuracy gains of up to 8.8 percentage points over capable-only execution. With Kimi K3 handing off at 45 percent progress, accuracy reached 72.57 percent against a 73.45 percent capable-only baseline while cost fell 61.5 percent. The caveat: handoff points were relative to a measured baseline trajectory, and later handoffs on DeepSWE generally reduced cost but also lost accuracy.
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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.