Simulating the Lateral Reader for News Trustworthiness Reports with an Iterative Multi-Agent RAG System
TL;DR
An iterative multi-agent Retrieval-Augmented Generation (RAG) system that operationalizes an iterative workflow of asking investigative questions, searching for external evidence, and synthesizing findings with attribution for the TREC 2025 DRAGUN Track.
Abstract
Readers of online news often lack the time and domain expertise required to verify unfamiliar claims and sources. Professional fact-checkers address this gap through lateral reading, an iterative workflow of asking investigative questions, searching for external evidence, and synthesizing findings with attribution. We present an iterative multi-agent Retrieval-Augmented Generation (RAG) system that operationalizes this workflow for the TREC 2025 DRAGUN Track. Given a news article, specialized agents (1) generate investigative queries, (2) retrieve and filter evidence from the MS MARCO V2.1 Segmented Corpus using a three-stage retriever (BM25+RM3, cross-encoder reranking, and LLM-based selection), and (3) apply an information-sufficiency evaluator that decides whether additional searching is required before writing. The final report generator produces a 250-word trustworthiness report grounded in retrieved segments, guided by automatically generated critical investigative questions. On the official DRAGUN rubric-based evaluation with 30 news articles, our system using GPT-4.1 ranked first on report generation quality, achieving the highest mean supportive score (0.230) with low contradiction (0.013).