Agentic Soft-Token Compression cuts a long-horizon agent's attention work by up to 50.68% without training anything
AspireAI community · arXiv
Long-horizon agents accumulate interaction context until it costs real compute and buries the evidence a decision actually depends on. Existing fixes train an external compressor or context-management agent to rewrite the history into short hard-token sequences, which is lossy and can drift from how the model now represents state. Agentic Soft-Token Compression instead uses the model's own recurrent dynamics - specifically the hybrid Gated Delta Network attention - to work out what has already been absorbed, then carries that forward as soft tokens while keeping exact values as hard tokens, which also yields reusable KV caches across the trajectory. On long-horizon tasks ASTC matched or exceeded the uncompressed agent's accuracy with up to 50.68% fewer end-to-end attention pairs, while trained compressors needed 15.4 to 103.7 times more attention pairs per successful task. It is training-free and depends on a hybrid architecture with recurrent layers, so it does not apply to a standard attention-only model.
Read the story and explore more from the AspireAI community.
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.