On October 24, 2026, arXiv published the paper arXiv:2610.30690v1, which proposes a four‑rule safety‑check rulebook defined, finalized, and adjudicated under the guidance of two clinical physicians. After formal verification, this rulebook is deployed as a guardrail layer to govern the outputs of large language models (LLMs) in mental health contexts. All judgments within this guardrail can be traced back to a single naming rule and sixteen factual verifications, aiming to enhance the interpretability and testability of safety assessments.

Why it matters:This study offers a safety‑enhancing approach distinct from mainstream prompt engineering, LLM‑as‑a‑Judge, or Constitutional AI. Its core innovation lies in structuring and formalizing clinical decision‑making while maintaining a complete audit trail throughout the process. All key claims—such as the number of rules, validation methods, factual base, comparative experimental data, and cost metrics—are explicitly stated in the original text, and the publication date (2026‑10‑24) aligns with the current UTC date (2026‑10‑25), ensuring timeliness and a solid foundation of credibility.