Team Gazoo! at #SMM4H-HeaRD 2026: Zero-Training NER via Iterative LLM Prompt Self-Optimization for Opioid Impact Span Detection

Diego Estuar


Abstract
This paper describes the system submitted by Team Gazoo! for Task 7 of the #SMM4H-HeaRD 2026 shared task on detecting self-reported clinical and social impacts of nonmedical opioid use in social media text. We present a zero-training, prompt-only approach that uses a large language model (GPT-5.4) with structured few-shot prompting and autonomous, iterative rule optimization. Our system encodes a domain-specific entity ontology, three core decision rules, and 65 cognitively organized few-shot examples into a single prompt, with BIO constraint enforcement applied as post-processing. Crucially, the prompt itself is refined by the LLM: at each iteration the model analyzes its own errors and proposes targeted edits to its rules and examples. Through 18 such self-refinement cycles, our system achieved an F1-Strict of 0.53 and F1-Relaxed of 0.60 on the test set, ranking first among all participating teams under both evaluation criteria.
Anthology ID:
2026.smm4h-1.6
Volume:
Proceedings of the 11th Social Media Mining for Health Research and Applications (SMM4H-HeaRD 2026) Workshop and Shared Tasks
Month:
July
Year:
2026
Address:
San Diego, United States
Editors:
Guillermo Lopez-Garcia, Graciela Gonzalez-Hernandez
Venues:
SMM4H | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
28–35
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.smm4h-1.6/
DOI:
Bibkey:
Cite (ACL):
Diego Estuar. 2026. Team Gazoo! at #SMM4H-HeaRD 2026: Zero-Training NER via Iterative LLM Prompt Self-Optimization for Opioid Impact Span Detection. In Proceedings of the 11th Social Media Mining for Health Research and Applications (SMM4H-HeaRD 2026) Workshop and Shared Tasks, pages 28–35, San Diego, United States. Association for Computational Linguistics.
Cite (Informal):
Team Gazoo! at #SMM4H-HeaRD 2026: Zero-Training NER via Iterative LLM Prompt Self-Optimization for Opioid Impact Span Detection (Estuar, SMM4H 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.smm4h-1.6.pdf