Journal article
What Counts as a Control? A Scaffold Effect Is a Contrast Conditional on What Was Held Fixed, the 2026 Controlled Studies Each Held Something Different, and Only a Declared Spend Interval Makes a Harness Claim Refutable
A language-model agent is a model wrapped in a harness that builds its context, exposes its tools, decides when to retry and when to stop. Several 2026 studies set out to measure how much the harness matters relative to the model, holding the model and the tasks fixed, and their answers do not…