A Qwen3-8B trained with reinforcement learning beat Llama-4-Maverick at 402B on tool selection, so you may not need a frontier model to pick tools
AspireAI community · Meta and Carnegie Mellon University (arXiv)
When an agent works over a catalogue of more than ten thousand tools, the bottleneck is picking the right ones: descriptions will not fit in context, and relevance retrievers rank without knowing what is actually needed. Current pipelines lean on a proprietary commercial model to drive the retriever, decomposing the instruction and selecting over retrieved candidates. This work shows a small open model trained with reinforcement learning can do the same job. On ToolBench, a Qwen3-8B post-trained with the recipe outperforms Llama-4-Maverick at 402B parameters, and the trained model transfers directly to different retrievers and generalises to new tool corpora in different domains. The practical payoff is cost and control: an 8B model you host yourself replaces a proprietary API call sitting in the hot path of every agent step. The open question is whether the comparison holds on tool catalogues shaped differently from ToolBench, since that is the corpus the result was measured on.
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.