A Self-Reflective LLM-based Architecture for Semi-Open Event Extraction
Paper · 2026 · Hristo Tanev, Michel de Bollivier and Bertrand De Longueville
Summary
Event extraction usually involves a trade-off. Closed schemas such as ACE or ERE keep outputs consistent but miss information outside the template. Open event extraction is flexible but can yield inconsistent records. The authors, from the European Commission's Joint Research Centre, propose Semi-Open Event Extraction (SOEE). A user-defined core of fields (event type, date, location and others) stays fixed, and further attributes are added at runtime depending on the article.
Their prototype, MAREA, is a three-layer multi-agent system built on a generative LLM:
- Expert layer: builds a few-shot initial template and answers questions.
- Reflective layer: asks itself about missing event details and proposes new fields.
- Coordination layer: a manager agent controls the workflow.
On health-related news articles, MAREA extracted core fields well, and most reflection-added fields were judged useful. Errors came mostly from misread prompts or misread articles rather than hallucination. The approach matters because it offers comparable records for event databases while still capturing context-specific detail, and its reliable fields could seed silver-standard corpora.
Key points
- Reflection mechanism: an internal question-generation and answering loop with three question strategies, one of them keyword-based. A spatial reasoning agent uses spaCy to find place names, and the LLM then assigns each place a role (e.g., place of infection), creating new candidate fields.
- Core-field F1: high for where-country (0.986), measures taken (0.941), actors (0.931) and event_type (0.901). Weaker results were for where-place (0.560) and when-end (0.462).
- Quality of reflection-added fields: 36% high, 20% medium, 12% low, 5% irrelevant and 24% duplicates.
- BERT-suggested questions: micro precision 0.7201, recall 0.4381 and F1 0.5448, which corresponds to a miss probability of about 0.4 in a small-scale test.
- Limitations: a single annotator, small samples and one domain. Planned work includes prompt optimization (e.g., MIPROv2), post-processing filters, other LLM backends, and new domains such as security and disaster relief.
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
🧭 Topics 1Research subjects and languages the work is about.Information extraction · 175 works
Cite
Cite as Hristo Tanev, Michel de Bollivier and Bertrand De Longueville. 2026. A Self-Reflective LLM-based Architecture for Semi-Open Event Extraction. Proceedings of the 9th Workshop on Event Extraction and Understanding: Challenges and Applications (EEUCA 2026).
@inproceedings{tanev2026self,
title = {{A Self-Reflective LLM-based Architecture for Semi-Open Event Extraction}},
author = {Hristo Tanev, Michel {de Bollivier} and Bertrand {De Longueville}},
booktitle = {Proceedings of the 9th Workshop on Event Extraction and Understanding: Challenges and Applications (EEUCA 2026)},
year = {2026},
doi = {10.18653/v1/2026.eeuca-1.8},
url = {https://doi.org/10.18653/v1/2026.eeuca-1.8}
}References
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