lilianweng.github.ioarticleHarness Engineering for Self-Improvement
Lilian Weng's long-form post argues that the "harness" surrounding a base model — the system that orchestrates planning, tool use, context, memory and evaluation — is as important to recursive self-improvement (RSI) as raw model intelligence. It surveys harness design patterns (workflow loops, file-system-as-memory, sub-agents) and traces an optimization progression from prompts to context engineering (ACE, Meta Context Engineering) to workflow search (ADAS, AFlow) to self-editing harness code (STOP, Self-Harness, Agentic Harness Engineering, Darwin Gödel Machine, Hyperagents) and evolutionary program search (AlphaEvolve, ShinkaEvolve). It closes with open problems for auto-research and self-improving agents: weak evaluators, memory/context lifecycle, negative-result bias, diversity collapse, reward hacking, and the durable need for human oversight, plus a benchmark appendix (PaperBench, CORE-Bench, RE-Bench, MLE-bench, KernelBench). Note: the fetched text is truncated partway through the references/appendix.
agents, coding-agents, research· 2026-07-04T00:00:00+00:00