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arXiv · 2610.11650

SkillContrast: Difference-Guided Text Selection for Agent Skill Reranking

Jiandong Ding·Honglei Ji·Ming Liu·Tao Duan
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Abstract

Similar agent skills can share instructions but differ in their conditions of use. Query-based text selection may retain shared instructions and omit these distinctions. We introduce SkillContrast, a training-free selector that compares retrieved skills and retains their differing text with local context for a pretrained reranker. On 1,235 requests from SameCapRisk-Bench, it yields 54-72 more clean hits (requests that retrieve a helpful skill without its marked risky sibling) than TF-IDF query selection at identical per-candidate input lengths, across 2 retrievers and 2 reranker sizes. Length-matched component replacements identify differing text as the main contributor in the primary setting, with smaller, mixed context effects. Relative to full skill bodies, SkillContrast uses 51.1-58.8% fewer model-input tokens, with 10-18 fewer clean hits at 0.6B and matching or higher observed clean-hit counts at 4B. Candidate-relative differences thus complement query relevance in selecting compact reranking inputs.

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Jiandong Ding, Honglei Ji, Ming Liu, Tao Duan. 2026-10-08. SkillContrast: Difference-Guided Text Selection for Agent Skill Reranking. https://arxiv.org/abs/2610.11650

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