研究复杂指令叠加对大模型执行能力的影响,发现指令冲突会导致准确率暴跌至20%。
Instruction Stacking Collapse: A Benchmark and the Capability-Dependent Value of Prompt Compilation

- 通过逐层叠加24条验证过的指令,构建真实场景下的多约束评估基准。
- 指令叠加导致遵循率从96%降至最低20%,主要由成对冲突引发。
- 无需训练的指令编译器可提升弱模型性能,适合生产部署中的低算力场景。
实际应用中的提示词很少只包含单一指令,可能同时要求输出为合法JSON、控制字数、引用三篇文献并保持固定语气。本文研究此类约束累积对指令遵循能力的影响。提出一个基准,逐步叠加24条经验证器校验的指令(每次1到20条),评估三个生产级大模型(Claude Sonnet 4.6、GPT-5-mini、Gemini 2.5 Flash)。结果显示,指令遵循率呈非线性下降:从约96%降至最低20%,根源在于可复现的成对冲突——例如,仅“输出JSON”这一要求就与另外九项要求无法共存。随后评估一种免训练的修复方法:通过单次大模型调用重写堆叠提示,并在多个查询中复用。该方法收益具有能力依赖性:对较弱模型最高恢复11个百分点的遵循率,而强模型因已内化结构,基本不受影响。通过聚类稳健性测试、同基线对照和家族内缩放阶梯分析,确认增益源于重写机制本身,而非额外token、顺序调整或测量空间。论文发布完整基准、验证器及缓存运行结果以支持完全复现。
原文摘要 · Abstract (English)
Production prompts rarely carry a single instruction. One system message may require valid JSON, a word limit, three citations, and a fixed tone at the same time. We study how instruction-following degrades as such constraints accumulate. We introduce a benchmark that stacks 24 verifier-checked instructions, one to twenty at a time, and evaluate three production-tier LLMs (Claude Sonnet 4.6, GPT-5-mini, Gemini 2.5 Flash). Instruction-following degrades non-linearly: the follow rate falls from ~96% to as low as 20%, driven by a structured and reproducible set of pairwise conflicts. A single "output JSON" constraint, for example, is jointly unsatisfiable with nine others. We then evaluate a training-free remedy: an instruction compiler that rewrites the stacked prompt in a single LLM call and is reused across queries. Its benefit is capability-graded. It recovers up to +11 points of follow rate for weaker models, which are also the models most often deployed at scale, while leaving stronger models, which already internalise the same structure, essentially unchanged. Cluster-robust tests, same-baseline controls, and a within-family scaling ladder attribute the gain to the rewrite itself rather than to additional tokens, reordering, or measurement headroom. We release the benchmark, verifiers, and cached runs for full reproduction.
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