On-Device Deep Research at 4B: Exposure Bounds Faithfulness, Retrieval Bounds Coverage

Jul 15, 2026

A new preprint investigates citation faithfulness and coverage in a 4B-parameter on-device research agent. The study finds that increasing the amount of each source the model sees ('exposure') significantly improves citation faithfulness, while the ability to retrieve relevant sources ('retrieval recall') limits trustworthy coverage. The authors recommend first maximizing per-source exposure, then focusing on improving retrieval recall to further enhance citation quality.

Why it matters: This work offers practical guidance for improving the reliability of citations in small, on-device research agents by disentangling the roles of exposure and retrieval.

Full story at: arXiv AI/ML ↗