Document Retrieval Augmented Fine-Tuning (DRAFT) for safety-critical software assessments
Regan Bolton, Mohammadreza Sheikhfathollahi, Simon Parkinson, Vanessa Vulovic, Gary Bamford, Dan Basher, Howard Parkinson
TL;DR
This work introduces Document Retrieval-Augmented Fine-Tuning (DRAFT), a dual-retrieval, fine-tuning framework designed to improve safety-critical software compliance assessment by jointly querying both documentation and applicable standards. Building on RAFT, DRAFT uses a dual retriever, a distractor-aware fine-tuning dataset, and LoRA-based optimization to enhance evidence-based reasoning and traceability. In experiments with GPT-4o-mini, the approach yields a 7% improvement in correctness over a baseline, with notable qualitative gains in evidence handling, answer structure, and domain-specific reasoning. Although gains are modest, the method offers a practical pathway to more reliable, transparent regulatory assessments in high-stakes domains, particularly when resources or model capability necessitate specialized tuning.
Abstract
Safety critical software assessment requires robust assessment against complex regulatory frameworks, a process traditionally limited by manual evaluation. This paper presents Document Retrieval-Augmented Fine-Tuning (DRAFT), a novel approach that enhances the capabilities of a large language model (LLM) for safety-critical compliance assessment. DRAFT builds upon existing Retrieval-Augmented Generation (RAG) techniques by introducing a novel fine-tuning framework that accommodates our dual-retrieval architecture, which simultaneously accesses both software documentation and applicable reference standards. To fine-tune DRAFT, we develop a semi-automated dataset generation methodology that incorporates variable numbers of relevant documents with meaningful distractors, closely mirroring real-world assessment scenarios. Experiments with GPT-4o-mini demonstrate a 7% improvement in correctness over the baseline model, with qualitative improvements in evidence handling, response structure, and domain-specific reasoning. DRAFT represents a practical approach to improving compliance assessment systems while maintaining the transparency and evidence-based reasoning essential in regulatory domains.
