Harness-Is-The-Differentiator Thesis

Description

The paper's signature cross-cutting thesis: frontier coding models converge in capability (top 3 within 1% on SWE-bench), so the operational harness — context management, safety layering, recovery, extension composition — becomes the real differentiator, not the model or the scaffolding. Corollary: the agent loop is easy to copy (a while-true around a model call), but hooks, classifier, compaction, and isolation are not.

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Sources

src-20260423-0cff68d3291b src-20260423-fd74bb3399e6