Pollux: A Compact Judge and Workflow for Criteria-Based LLM Evaluation

Ulyana Isaeva, Maslennikov Egor, Alisa Glushko, Nikita Martynov, Anastasia Mordasheva, Gorbetskiy Dmitriy, Elina Basyrova, Sergey Skachkov, Berestova Victoria, Alena Fenogenova, Danil Astafurov


Abstract
Evaluating open-ended generation remains non-trivial because quality varies across style, correctness, grounding, and safety. Moreover, a fixed prompt-response abstraction is insufficient for a reusable evaluation system as deployed applications increasingly expose multi-turn dialogues, retrieved evidence, and tool-calling traces. We present Pollux, a universal criteria-based evaluation framework centered on Pollux Judge, a compact Qwen3-4B-based LLM-as-a-Judge that evaluates such heterogeneous interactions through free-form user-defined criteria, scales, and output formats. Pollux follows the criteria methodology represented in the Pollux Benchmark (35 task groups, 2,115 expert-authored prompts), using it as a human-grounded resource for judge validation. The judge is trained with GRPO on Russian- and English-language data and is designed for bilingual deployment through a language-independent interaction schema. On the held-out expert-labeled test set, Pollux reaches a Spearman correlation of 0.744, exceeding every evaluated general-purpose baseline, including models with up to 1.1T parameters, while remaining suitable for local or OpenAI-compatible serving.

System demonstration video: https://drive.google.com/file/d/1PF6L-RcrS24JVUdaVRi01j237yTdftEd/
Anthology ID:
2026.aacl-demo.7
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics: System Demonstrations
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Ningyu Zhang, Derry Wijaya
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
50–57
Language:
URL:
https://aclanthology.org/2026.aacl-demo.7/
DOI:
Bibkey:
Cite (ACL):
Ulyana Isaeva, Maslennikov Egor, Alisa Glushko, Nikita Martynov, Anastasia Mordasheva, Gorbetskiy Dmitriy, Elina Basyrova, Sergey Skachkov, Berestova Victoria, Alena Fenogenova, and Danil Astafurov. 2026. Pollux: A Compact Judge and Workflow for Criteria-Based LLM Evaluation. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics: System Demonstrations, pages 50–57, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
Pollux: A Compact Judge and Workflow for Criteria-Based LLM Evaluation (Isaeva et al., AACL-IJCNLP 2026)
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PDF:
https://aclanthology.org/2026.aacl-demo.7.pdf