Peer-review–based translator training promotes reflection and collaborative critique. This study examines whether GPT5, guided by MQM-like prompts, can function as a peer-review training partner rather than a grading tool. Using translated passages from a practice group, we compared GPT5’s feedback with human evaluations of the same segments, including both negative and positive judgments. GPT5 aligned with human evaluators on 77.8% of negative flags and 88.9% of positive flags, and achieved an F1 score of 0.875 for detailed rationales supporting the flags. The results suggest that GPT5 can provide useful analyses and alternative perspectives that support learner reflection, although its occasional poor judgments indicate that it should be used as a supplementary training partner rather than a standalone evaluator.