01In plain English
Before the model answers, the tool searches a set of documents, such as your help centre or files, and passes the most relevant passages to the model. The answer is then based on that material rather than on the model's memory alone.
02Why it matters when you are choosing
Most support bots and "chat with your documents" tools work this way. It makes answers more accurate and lets them cite sources, but they are only as good as the documents behind them.
03What to check
Ask the vendor
Check which sources it can connect, how often it re-reads them, and whether answers show where they came from.