Harness Updating Is Not Harness Benefit: Disentangling Evolution Capabilities in Self-Evolving LLM Agents

This paper disentangles two self-evolving LLM agent capabilities: harness-updating (producing useful updates) and harness-benefit (gaining from these updates). The analysis reveals that harness-updating is surprisingly consistent across models of different base capabilities, suggesting that even less capable models can produce useful updates.