L52+-IIMAS-UNAM at SemEval-2026 Task 1 (MWAHAHA): Joke Selection Through a Multi-Stage Prompt-Engineering and Heuristic Pipeline

Adolfo Tonatihu Camacho Gonzalez, Ximena Cruz, Natalia Godínez-Aldana, Lizeth Palacios-Patiño, Ramón Rangel, Ivan Vladimir Meza Ruiz


Abstract
Humor generation remains one of the most challenging tasks in natural language processing, requiring creativity, incongruity resolution, cultural sensitivity, and strict structural control. We present a fully prompt-based system for headline-conditioned joke generation in SemEval-2026 Task 1 (MWAHAHA) for both English and Spanish. Deliberately avoiding fine-tuning, our approach relies on structured prompt engineering combined with a multi-stage heuristic pipeline. For Spanish, we extract a “stylistic-humor DNA” from a public joke corpus to guide generation. The pipeline integrates multi-candidate generation, diversity enhancement, iterative refinement, LLM-based rewriting, and constraint-aware selection. Human evaluation performed by the team (n=180) shows substantial gains over single-pass generation, particularly in funniness and punchline clarity. Official shared-task results were modest (12th/16 Spanish, 24th/31 English), underscoring that limited originality remains a key bottleneck. In an era dominated by large language models (LLMs) such as GPT-4o and Grok, our work demonstrates the value of linguistically grounded heuristics as an efficient, interpretable, and low-cost complement to black-box generation systems.
Anthology ID:
2026.semeval-1.291
Volume:
Proceedings of the 20th International Workshop on Semantic Evaluation (2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Ekaterina Kochmar, Debanjan Ghosh, Kai North, Mamoru Komachi
Venues:
SemEval | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2301–2306
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.291/
DOI:
Bibkey:
Cite (ACL):
Adolfo Tonatihu Camacho Gonzalez, Ximena Cruz, Natalia Godínez-Aldana, Lizeth Palacios-Patiño, Ramón Rangel, and Ivan Vladimir Meza Ruiz. 2026. L52+-IIMAS-UNAM at SemEval-2026 Task 1 (MWAHAHA): Joke Selection Through a Multi-Stage Prompt-Engineering and Heuristic Pipeline. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 2301–2306, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
L52+-IIMAS-UNAM at SemEval-2026 Task 1 (MWAHAHA): Joke Selection Through a Multi-Stage Prompt-Engineering and Heuristic Pipeline (Camacho Gonzalez et al., SemEval 2026)
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https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.291.pdf