Evidence-Aware Human-in-the-Loop LLM Review for Requirements-to-Planning Decisions

Large language models can produce fluent requirements refinements and planning artifacts while still leaving information unresolved for implementation, testing, or planning commitment. This paper presents ReqPlan-Eval, an evidence-aware human-in-the-loop architecture that connects NFR disagreement, weak-word cues, planning-relevant ambiguity, and role-specialized hypotheses to inspectable planning-support records and configurable review routes. The empirical study evaluates the principal mechanisms and role-based routing signals on separate datasets; it does not constitute an end-to-end evaluation of the complete pipeline on a common set of requirements. A held-out 500-requirement NFR diagnostic achieved exact-match accuracy of 0.716, micro F1 of 0.702, and quality accuracy of 0.874. Pattern-aware arbitration increased weak-word specificity from 0.572 to 0.676 and review precision from 0.678 to 0.724, while component/goal gating increased ambiguity specificity from 0.380 to 0.908 and F1 from 0.748 to 0.855; both mechanisms lost recall. In Experiment 3, four role-specialized outputs were compared with a model-seeded reference reviewed and adjudicated by three human reviewers. On the 20 public stories, role-level exact agreement for validation_needed was 0.825, and a two-or-more-vote policy reviewed 12 stories and captured 12 of 14 reference positives without routing any of the six reference negatives. Open-ended planning artifacts showed very low exact normalized-item overlap with the reference for tasks, acceptance criteria, and test ideas, so no semantic-agreement claim is made for those artifacts. Seven external participants provided initial face-validity evidence for selective review and human control. The results support the evaluated component mechanisms and selective review routing under the frozen configurations, but they do not establish end-to-end workflow effectiveness, model invariance, better planning decisions, or industrial effectiveness.