検索拡張生成の必要性

LLMs are incredible at writing, answering, and coding — but they carry real limitations that make them unreliable for certain tasks. Let us look at why.

The first problem is hallucination: an LLM confidently presents false info as fact. It is not lying — it is guessing from patterns, and the made-up answers sound convincing.

Picture a brilliant student who stopped learning on a fixed date — that is the knowledge cutoff. LLMs cannot see anything after their training ended.

LLMs rarely tell you where an answer came from — no sources, no citations. That missing transparency makes their claims hard to verify.

So LLMs struggle with factual accuracy, fresh information, and verifiability. The big question: how do we make them reliable enough for real-world use?

The answer is Retrieval Augmented Generation (RAG): it pairs an LLM with external, verifiable knowledge — essentially giving it an open-book test.

RAG boosts accuracy: before the LLM answers, it retrieves relevant info from a trusted source. That context guides the model instead of letting it guess.

RAG also fixes freshness: hook it to continually updated sources — internal docs, live feeds, a knowledge base — and the LLM always sees current information.

RAG adds trust: since answers are grounded in specific retrieved documents, the system can cite exactly which sources it used, making verification easy.

The core of RAG is two steps: retrieve relevant info for the query, then generate an answer using that context — keeping the LLM grounded.

You learned why RAG matters: it cures hallucinations and stale knowledge by feeding LLMs external, current, verifiable info — for accurate, transparent answers.