Hey Cezary! Thanks for the very useful guide. I have an idea of a custom GPT but I wonder if it is overly ambitious at this point in time, both for GPT builder and my own lack of experience. What do you think? Here is the idea.

I am a software developer working in Web applications, building front ends for certain networking products. I've been working several years on a quite complex app -- tons of code in hundreds of files. I am going to retire in a year and I feel sorry for the poor engineer (or engineers) who will take over for me. I wonder if a custom GPT will be useful if I give it all of the source code and the Theory of Operations document and User Guide. Plus maybe some product specifications, maybe even the support ticket database. Do you think the GPT could make sense of all that? What else could I provide or train to make it a useful tool for the new engineer(s)?