AWS shipped a hands-on multi-turn RL recipe for SageMaker AI, and gpt-oss-20b went from a 61% to an 84% solve rate in one run
AspireAI community · Amazon Web Services
AWS published an end-to-end guide to Multi-Turn Reinforcement Learning on Amazon SageMaker AI, where the training job drives a hosted agent, the agent acts over many turns and reports a single reward at the end, so the credit assignment spans the whole trajectory instead of one prompt. In their reference run on a Wordle environment, MTRL took gpt-oss-20b from a 61% to an 84% solve rate on held-out words at its default reasoning effort, and from 15% to 69% at the low effort it trained at, for about $339 in training tokens. The post covers deploying the agent and reward to Amazon Bedrock AgentCore, dataset preparation, training, MLflow monitoring and evaluation at serving settings, and it says the data and trained model stay in the customer's AWS account. Caveat: Wordle is a teaching example that frontier models already play well, and this is one AWS run on one task at a fixed reasoning setting rather than a general agentic-RL benchmark.
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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.