Addressed in 12bacdf09 — added a review-handler test asserting the model is never invoked when the PR has no actionable diff (empty/unpatched files route to the no-files abort: `askAI` not called, `updateStartedReviewNoFiles` called once). Note: the line-147 empty-diff guard is currently belt-and-suspenders since `filterFiles` already drops patch-less files, so the reachable empty-content path is the no-files branch — that's what the new test exercises.