LLM-INSTRUCT at UZH Shared Task 2026: Constraint-Aware Retrieval and Selective Debate for Paragraph-Level Argument Mining
Paper · 2026 · Phuong Huu Vu Tran, Long Minh Vo, Son Nguyen Minh Le et al.
Summary
LLM-INSTRUCT won the UZH Shared Task at ArgMining 2026. The task asks systems to analyze paragraphs of UN and UNESCO resolutions in three ways: label each paragraph as preambular or operative, assign a subset of 141 official thematic tags, and predict labeled directed links between paragraphs. Output must follow a strict JSON schema, and only open-weight models of up to 8B parameters are allowed.
The authors treat this as constrained structured prediction rather than free generation. Paragraph type comes from a rule-based heuristic. For tags, intfloat/e5-base-v2 retrieves candidates using prototype strings built from organizer metadata. Qwen3-8B then chooses only from that retrieved set, under caps on the number of tags. Ambiguous cases go to a three-model debate. A final validation layer checks schema compliance.
The system ranked first overall. During development, its Task 1b Micro-F1 rose from 35.83% to 40.08%. The main takeaway is that shrinking the label space before generation improves both accuracy and the reliability of valid submissions. Recognition of rare tags remains weak.
Key points
- Data:
- The training release is unlabelled and comes from 2,695 UN resolutions in the UN-RES corpus (linked to SpiritRAG).
- Evaluation uses a held-out UNESCO split.
- Texts are in French, with English translations from the organizers. The system reads English when available.
- Official ranking: 1st overall, 1st in F1, and 5th in LLM-as-a-Judge. The internal Task 2 score was 4.421.
- Tag controls:
- Each tag is represented by a Dimension | Category | CODE prototype.
- Each paragraph gets at most 5 tags, with no more than 2 per dimension.
- The prompt includes up to 3 retrieved examples with similarity above 0.70.
- Ablations:
- Using CODE-only prototypes cut subset F1 by 7.74 points.
- Dropping retrieved examples cut subset F1 by 5.17 points.
- Tags with at most five occurrences reached only 2.51% F1.
- Debate and relations:
- The debate agents are Qwen3-8B, Llama-3.1-8B-Instruct and Ministral-8B-Instruct.
- Relation candidates combine a one-paragraph locality window with the top-6 most similar paragraphs. Edges need confidence ≥0.40, with at most 5 per source paragraph.
- The final output has 13,323 edges, a graph density of 10.03%.
- The full run took about 1h42m on 2×RTX 3090 GPUs.
Institutions
Fields, topics and concepts
📚 Shelves 6The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 worksSocial Sciences · 1,772 worksPolitical Science and International Relations · 182 works
🧭 Topics 1Research subjects and languages the work is about.Information retrieval & search · 473 works
Cite
Cite as Phuong Huu Vu Tran, Long Minh Vo, Son Nguyen Minh Le and Hoang Van. 2026. LLM-INSTRUCT at UZH Shared Task 2026: Constraint-Aware Retrieval and Selective Debate for Paragraph-Level Argument Mining. Proceedings of the 13th Workshop on Argument Mining and Reasoning.
@inproceedings{tran2026llm,
title = {{LLM-INSTRUCT at UZH Shared Task 2026: Constraint-Aware Retrieval and Selective Debate for Paragraph-Level Argument Mining}},
author = {Phuong Huu Vu Tran, Long Minh Vo, Son Nguyen Minh Le and Hoang Van},
booktitle = {Proceedings of the 13th Workshop on Argument Mining and Reasoning},
year = {2026},
doi = {10.18653/v1/2026.argmining-1.11},
url = {https://doi.org/10.18653/v1/2026.argmining-1.11}
}References
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