Training a large language model for open-ended generation usually needs a detailed scoring guide to provide feedback. If the rubric stays static while the model improves, the feedback becomes useless.
The proposed method, CoCA, contrasts normal responses with responses nudged by the rubric. This reveals what the model can only do with a hint. The rubric is adjusted to track this frontier, and the model either imitates the guided success or explores the frontier.
In tests across science and medical benchmarks, CoCA consistently beat standard methods, often reaching the same or better quality in about half the training steps. This shows that co-evolving the model and its feedback rubric saves compute and produces more capable text generators.
