https://blog.yushi91.com/blog/hallucination/Recent content in Hallucination on Yushi's BlogHugoen-USCopyright © 2025, Yushi Cui.Sat, 02 May 2026 10:00:00 +1200https://blog.yushi91.com/blog/rag-chatbot-say-i-dont-know/Sat, 02 May 2026 10:00:00 +1200https://blog.yushi91.com/blog/rag-chatbot-say-i-dont-know/<p><img src="https://blog.yushi91.com/rag-i-dont-know.webp" alt="Letting a RAG chatbot say I don&rsquo;t know" loading="lazy"> </p> <h2 id="the-moment-that-stuck-with-me">The moment that stuck with me</h2> <p>I already wrote about <a href="https://blog.yushi91.com/blog/first-rag-solution-semantic-search/">building my first RAG solution</a>, so I won&rsquo;t repeat the basics. What I want to talk about is one specific moment from that project. The moment the whole thing actually clicked for me.</p> <p>It wasn&rsquo;t the retrieval part, or the embeddings. It was watching the chatbot say &ldquo;I don&rsquo;t know.&rdquo;</p> <h2 id="the-superpower-nobody-warns-you-about">The superpower nobody warns you about</h2> <p>Once you bolt RAG onto a chatbot and tighten the prompt a bit, you unlock something a regular chatbot basically can&rsquo;t do. The bot can admit it doesn&rsquo;t have the answer.</p>