Google's 'Harness²' Lets Weaker Models Beat Stronger Ones by Rewriting Their Own Scaffolding Mid-Task

A new paper shows agents editing their own harness at runtime, with GLM-5 jumping 11.5 points — evidence that better scaffolding can outperform bigger models.

A Google paper on "Harness²," flagged by @itsharmanjot, offers a counterweight to the week's scale-everything narrative. The core finding: weaker models can outperform stronger ones when allowed to dynamically edit their own harness — the surrounding scaffolding of tools, prompts, and control flow — in the middle of a task. GLM-5 reportedly jumped 11.5 points under this approach.

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