This paper systematically categorizes four typical types of hallucinations exhibited by AI agents in real-world workflows—factual, contextual, fictional, and self-contradictory—and proposes that detection should rely on a multi-dimensional approach, incorporating credibility checks, source verification, self-consistency assessment, semantic entropy analysis, and human–machine collaboration thresholds, rather than on a single scoring metric. It underscores that such detection must be embedded within the workflow’s closed loop and deeply integrated with observability, error handling, and human review pathways.