Cloud and On-Premises Deployment of Uzbek Legal RAG via Targeted Retriever Fine-Tuning

Abstract:Deploying large language models for legal question answering raises challenges that general-purpose leaderboards do not capture, particularly for low-resource languages and under hard operational constraints. We report on building and operating a retrieval-augmented (RAG) legal assistant for Uzbek that must run in two regimes: a managed cloud service that maximizes answer quality within a per-token cost ceiling, and an on-premises deployment for clients whose legal data may not leave their infrastructure, restricting us to open-weight models on limited local hardware under latency constraints. Because no evaluation existed for this setting, we build two domain benchmarks: a retrieval benchmark of 178 expert-annotated legal queries with gold provision spans, and an end-to-end benchmark of 504 expert-curated question--answer pairs scored by an LLM judge whose ratings we validate against human judgments and against an independent-family judge. Applying these benchmarks under each regime, we find the open-versus-proprietary gap is small and cheaply closed by fine-tuning. Therefore, we train UTE-1, which is a state-of-the-art text embedder among open models for Uzbek. We also demonstrate that closing the performance gap via fine-tuning is both impractical due to the intensive hardware demands of long-context legal Q\&A and unnecessary, given that legal acts change frequently. We support this by reporting a negative result from a QLoRA experiment. We distill practical guidance for similar deployments, drawn from a system serving real users in production. We release our benchmarks, evaluation code and the fine-tuned embedder (UTE-1) \href{this https URL}{at this https URL} to support future work on low-resource legal NLP.

Accepted to EMNLP 2026 (Industry Track). Project home: [this https URL](this https URL)

Computation and Language (cs.CL); Information Retrieval (cs.IR)

arXiv:2608.29284 [cs.CL]

(or arXiv:2608.29284v1 [cs.CL] for this version)

https://doi.org/10.48550/arXiv.2608.29284 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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