Reinforcement fine-tuning for GUI agents broke down on new interfaces, and the grounding signal was the reason
AspireAI community · arXiv
GUI data is non-stationary: new domains and resolutions keep appearing and shift the distribution under any existing agent. Reinforcement fine-tuning is the common response, but it is unstable on grounding - rollout outcomes are imbalanced and fixed clipping suppresses exploration, and policy probability alone does not reveal the semantic role of a grounding prediction. GUI-AC is a continual reinforcement fine-tuning framework that characterises grounding rollouts by both advantage and policy probability, giving a four-region view of grounding behaviour and making it possible to target exploration and overconfidence separately. Two mechanisms follow: adaptive advantage strengthens the negative correction for overconfident grounding failures, and dynamic clipping relaxes the upper clipping bound for exploratory rollouts. The authors report consistent gains over state-of-the-art baselines, with code released.
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.