Google Researchers Add Regularization to Self-Improving AI Agent Harnesses
The paper argues that recursive self-improvement (RSI) of LLM agent harnesses—the prompts, control flow, tooling and memory scaffolding around a frozen model—tends to overfit training tasks, boosting in-distribution scores while gains on out-of-distribution benchmarks shrink or disappear. The authors propose RRSI, which regularizes both the proposal step (an annealed edit budget plus incentives to explore new trajectories) and the selection step (a critic to filter benchmark-specific edits and a pruner to remove trivial, costly, or stale changes), aiming to favor reusable agent mechanisms over narrow overfitting. Across eight coding, agentic-workspace, and engineering benchmarks, they report up to 14.1 points gain on the evolved split and up to 4.7 points on five held-out benchmarks, with the resulting harness using 30% fewer policy tokens than an unregularized version. Twitter posts from the authors (including a Google-affiliated contributor) simply announced the paper, code, and project page without additional critical discussion.
Discussion: 2 tweets from 2 authors · @HanRujun, @richardxp888