XGRAG: A Graph-Native Framework for Explaining KG-based Retrieval-Augmented Generation
Graph-based Retrieval-Augmented Generation (GraphRAG) improves how large language models (LLMs) answer questions by providing them with structured, context-rich information from knowledge graphs. While this makes answers more grounded, the reasoning process remains a "black box," making it difficult to determine which specific pieces of information actually influence the final output. This paper introduces XGRAG, a framework designed to bring transparency to these systems by quantifying how individual components of a knowledge graph contribute to an LLM's response.
The Problem with Black-Box Reasoning
Current explainability methods for RAG systems were primarily designed for text-based retrieval. These methods struggle to interpret the complex, relational structures found in knowledge graphs. Because these existing tools cannot effectively map how specific graph connections lead to an LLM's answer, there is a significant gap in the transparency and trustworthiness of GraphRAG systems. Users often cannot see the "why" behind a model's conclusion, which limits the reliability of these systems in practical applications.
How XGRAG Works
XGRAG addresses this transparency gap by using a "graph-native" approach. Instead of treating the knowledge graph as simple text, the framework employs graph-based perturbation strategies. By systematically perturbing—or slightly altering—individual components of the graph, the system can measure how those changes affect the LLM's final answer. This allows XGRAG to calculate the specific contribution of each graph element, effectively mapping the causal link between the structured data and the generated response.
Performance and Validation
To test the effectiveness of the framework, the researchers compared XGRAG against RAG-Ex, an existing explainability baseline for standard RAG systems. The experiments, conducted across datasets like NarrativeQA, FairyTaleQA, and TriviaQA, showed that XGRAG achieved a 14.81% improvement in explanation quality, measured by the F1-score alignment between the generated explanations and the model's original answers. Furthermore, the researchers found that XGRAG’s explanations correlate strongly with graph centrality measures, confirming that the framework successfully captures and interprets the underlying structure of the knowledge graph.
Toward Trustworthy AI
By providing a scalable and generalizable method for interpreting GraphRAG, XGRAG represents a step forward in making AI systems more transparent. The framework’s ability to offer clear, graph-based explanations helps bridge the gap between complex machine reasoning and human understanding, ultimately contributing to the development of more trustworthy and interpretable AI technologies.

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