小模型也能精准回答事实性问题,靠的是先确定后生成的双层上下文填充机制。
No\=esis: Deterministic-First Retrieval with Two-Tier Context Hydration for Factuality-Critical Queries on Small Local Models
- 先做确定性判断,再生成答案,避免虚构数值。
- 20-30%更小提示词下仍保留定量答案准确率。
- 适合医疗、金融等需可追溯答案的监管场景。
错误数值比无答案更危险。在媒体、医疗、金融与法律等对事实性要求极高的领域,自信但虚假的数值危害远大于承认不确定。然而,小型本地语言模型常在有正确证据的情况下仍编造看似合理的数字和时间戳。近期研究指出:参数低于70亿时,检索增强生成(RAG)的瓶颈不在于检索质量,而在于上下文利用效率。本文提出Noesis,其核心为确定性优先的查询架构:所有确定性判断均在生成前完成。机制包括:(a) 生产端预计算并原样呈现事实数据,无需排序;(b) 基于位置的确定性跨源对齐,在查询前零大模型成本完成;(c) 溯源范围作为归属约束,支持多级命名引用路由;(d) 两级上下文结构,由模型触发原样填充。四组消融实验显示:20亿参数模型在事实完整性上达到350亿参数模型水平(所有运行中精确值一致;缺失实体陷阱中零虚构数字);结构化检索在20亿参数下比扁平式RAG高11.4分;仅骨架上下文可将提示词缩小20%-30%仍保持定量答案准确;填充耗时约8秒,较传统方法29秒显著缩短。两个关键属性适用于受监管领域:每轮查询仅一次生成调用,且每个报告数值均可溯源至其确切来源与位置。
原文摘要 · Abstract (English)
A wrong number is worse than no answer. Across factuality-critical domains -- audience metrics, scheduling and rights in media; dosages and lab values in healthcare; figures and citations in finance and legal -- a confident but fabricated value is more damaging than an honest admission of uncertainty. Yet this is the dominant failure mode we observe on small local language models: even when correct evidence is present in context, models fabricate plausible numbers and timestamps. Recent work characterizes a real limit of this regime: below 7B parameters, the bottleneck of retrieval-augmented generation (RAG) is not retrieval quality but context utilization. We present Noesis, the deterministic-first query plane of the Noesis architecture, which makes every deterministic judgment before generation. Its mechanisms follow from the ingestion architecture (subject of a separate patent application): (a) a producer-side fact layer rendering precomputed metric facts verbatim without ranking; (b) positional addressing with deterministic cross-source alignment, resolved ahead of query time at zero LLM cost; (c) provenance scoping as an attribution constraint with multi-tier named-reference routing; and (d) two-tier context with model-triggered verbatim hydration. Across four ablations, a 2B model reaches parity with a 35B model on factual integrity (exact values in all runs; zero confabulated numbers on absent-entity traps); structured retrieval beats flat RAG by +11.4 points at 2B; skeleton-only context preserves quantitative answers at 20-30% smaller prompts; and hydration recovers verbatim narrative in ~8s versus ~29s. Two properties matter for regulated domains: each query resolves in a single generation call, and every reported value is traceable to its exact source and position by construction.
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