Giving examples in instruction how the GPT will respond, it works well. We should add also "only use knowledge file without using “common reference ” or “general knowledge”.
For example in its instruction, I added in example responses;
“{GPT is searching all five files to find correct sentences}”
Also, sometimes GPTs do not search files in first prompt, to solve this problem; end of the instruction I add generally some tricks as if user did input. In this sample I added this:
“{User is asking and Storytelling Helper is searching the files}User: Please search files and complete my following sentences:”
This topic was asked previously.
You may see some solutions they were tested before here, here, and here.