Context-Engineering

AI Self-Improvement Starts Outside the Model

When people talk about AI self-improvement, the usual image is a model rewriting its own weights. Lilian Weng’s July 4, 2026 post on Lil’Log argues the near-term version looks different. The recursive self-improvement (RSI) we can actually observe today shows up first in the system around the model, not inside it. That system is what she calls the harness. This post walks through her argument: what a harness is, where the optimization target is moving, what a striking SWE-bench number actually means, and what breaks if you get the risk boundaries wrong.

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