Book: LLM Observability Pocket Guide: Picking the Right Tracing & Evals Tools for Your Team Also by me: Thinking in Go (2-book series) — Complete Guide to Go Programming + Hexagonal Architecture in Go My project: Hermes IDE | GitHub — an IDE for developers who ship with Claude Code and other AI coding tools Me: xgabriel.com | GitHub A customer pasted three sentences from the assistant into a ticket. The first cites a paper from 2024 that does not exist. The second sentence contradicts the third. None of them appear anywhere in the document the user actually uploaded. If you are running a single hallucination check against that paragraph, you will catch one of those three problems and miss the other two. They are not the same defect. They come from different failure modes and need different detectors. Treating "hallucination" as one bucket is why your eval suite passes while support escalates. The Ji et al.…