Yam at SemEval-2026 Task 4: Failure-Driven Prompt Evolution for Narrative Comparison
Paper · 2026 · Yen Yee Yam and Hong Meng Yam
Summary
The paper tackles SemEval-2026 Task 4 (Narrative Story Similarity, Track A). Each item gives an anchor story and two candidates, and the system must pick the candidate that is narratively closer in abstract theme, course of action, and outcome. The authors do not measure distance between embeddings. Instead they build a prompt-only pipeline around GPT-5.2 and never change its weights. Each story is first analysed separately along the three task dimensions. The model then compares the candidates one dimension at a time and justifies each judgment before giving a final answer. A feedback loop then examines misclassified items, finds recurring errors in both extraction and comparison, and rewrites short guideline documents. Any rewrite that lowers accuracy is rolled back. Decomposition alone reaches 70% on both train and test, and the evolved guidelines lift this to 76% and 73%. The authors argue that part of the improvement usually credited to fine-tuning can come from better-structured reasoning alone.
Key points
- Ablation on Track A (train/test accuracy): direct prompting 69%/68%, ontology-aligned decomposition 70%/70%, decomposition plus self-improvement 76%/73%.
- The optimisation loop maintains three length-limited guideline documents: decision-level comparison guidance, shared general reasoning principles, and intermediate extraction guidance.
- A revision is kept only if evaluation accuracy improves; otherwise the loop automatically reverts it, which limits drift.
- All runs use GPT-5.2 via API with no fine-tuning or RL. Repeated inference calls are combined by majority voting to reduce output variance.
- Stated limitations include dependence on a proprietary model, no direct comparison with fine-tuned baselines, a search procedure that may not reach an optimal strategy, and untested cross-domain robustness.
Institutions
Fields, topics and concepts
📚 Shelves 4The field of science this work belongs to (OpenAlex fields).Computer Science · 18,614 worksArtificial Intelligence · 17,965 worksArts and Humanities · 17,450 worksLanguage and Linguistics · 17,296 works
Cite
Cite as Yen Yee Yam and Hong Meng Yam. 2026. Yam at SemEval-2026 Task 4: Failure-Driven Prompt Evolution for Narrative Comparison. Proceedings of the 20th International Workshop on Semantic Evaluation (2026).
@inproceedings{yam2026yam,
title = {{Yam at SemEval-2026 Task 4: Failure-Driven Prompt Evolution for Narrative Comparison}},
author = {Yen Yee Yam and Hong Meng Yam},
booktitle = {Proceedings of the 20th International Workshop on Semantic Evaluation (2026)},
year = {2026},
doi = {10.18653/v1/2026.semeval-1.421},
url = {https://doi.org/10.18653/v1/2026.semeval-1.421}
}References
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