Not Every Passing Patch Deserves the Same Credit
TL;DR for operators A code agent can produce two patches that pass the same tests while differing sharply in precision, scope, side effects, and consistency with the repository. Gagar1 keeps executable tests as the success gate, but adds an agentic grader to rank the quality of successful implementations. The less obvious contribution is what happens after grading. Simply reducing the reinforcement assigned to weaker successful trajectories also reduces the group’s total positive credit. In the paper’s ablation, that design was accompanied by much faster growth in policy entropy and rollout length. Gagar instead redistributes positive advantage so better successful trajectories receive more relative credit while the original positive-credit total is preserved in the exact formulation. ...