Mitigating Hallucinations in Knowledge Graph Completion via Embedding-Guided Instruction Tuning

Real-world Knowledge Graphs (KGs) are inherently incomplete, which hinders effective downstream reasoning. While Large Language Models (LLMs) possess powerful semantic capabilities, directly applying them to Knowledge Graph Completion (KGC) often leads to hallucinations and a lack of structural awareness. To address these challenges, we propose Embedding-Guided Instruction Tuning (EGIT), a novel framework that synergizes the structural precision of embedding models with the semantic reasoning of LLMs. Our approach operates in three key stages: (1) utilizing pre-trained embedding models to automatically synthesize high-quality, annotation-free instruction data; (2) fine-tuning the LLM with these structure-aware instructions to adapt it to the KGC task; and (3) employing a joint inference mechanism where the embedding model retrieves candidates and the fine-tuned LLM performs the final selection, thereby significantly reducing hallucinations. In extensive experiments, the best variant of EGIT achieves 7.0% and 2.5% improvements in Hits@1 on the FB15k-237 and WN18RR datasets, respectively.