diff-eval-skill

Evaluate agent-generated code changes against a human-approved PR. Compares the local git diff (modified + untracked files, relative to the PR's merge base commit) with the ground truth PR diff, filters out auto-generated files, scores using a structured rubric (functional correctness, completeness, behavioral equivalence), and provides both semantic and data-based coverage analysis. Use when evaluating agent code generation quality, benchmarking AI coding tools, or comparing generated patches against human-approved pull requests. Trigger on "/diff-eval", "evaluate diff", "compare diff with PR", "score the changes".