Swap the harness, Astra's ARC-AGI-3 score drops from 98.6% to 62.7%
OpenAI's headline 98.6% ARC-AGI-3 figure for GPT-6 Astra only exists under its own Provider Adapter harness. ARC Prize's independent table shows the same model at 62.7% on the standard harness at max reasoning, falling to 17% at lower settings. When a benchmark swings that hard with scaffolding, it's measuring the harness, not the model.