Schema Harness Achieves 99% on ARC-AGI-3 by Thinking Like a Physicist

Schema Harness Achieves ~99% on Arc‑AGI‑3 Public

We introduce Schema, a new harness that pushes frontier models like Claude Opus 4.8 and GPT-5.6 Sol to achieve 99% on the ARC-AGI-3 Public set. Instead of changing model weights, Schema changes the process, forcing agents to jointly solve state grounding and mechanism discovery. By treating the world representation as an editable program, our system allows agents to revise their understanding of objects and rules when predictions fail, mirroring how physicists refine theories.

"When predictions fail persistently, they do not only adjust the law. They change what the state is."