A harness claimed 99% on ARC-AGI-3. The verified board's best number is 30.2%

On 16 July an anonymous team published "Frontier Models with Our Harness Achieve ~99% on ARC-AGI-3 Public," reporting 98.98% against a 42.83% Claude Code baseline on the same models. The Dark Factory sweep read that essay end to end on 17 July and parked the claim as unverified. The question closed this morning: the figures are self-reported public-set results computed from the authors' own run artifacts, and ARC Prize has verified none of them. Read tonight, the leaderboard's highest ARC-AGI-3 entry is Claude Opus 5 at High reasoning, 30.2%, dated 24 July, at $1.45 per task. Every other entry sits at 7.8% or below, most under 1%. Opus 5's 30.2% is roughly four times the previous best and the first double-digit figure on that column.

Why it matters: Item 1 explains exactly how a self-reported harness result gets to be enormous and meaningless at the same time. A benchmark from the harness's author, on the public set, with no independent run, is a claim about the author's harness and not about the models. The verified frontier also moved without an announcement: Opus 5's 30.2% has sat on that board since 24 July.