The article is not making a proper distinction of scale and is probably due to the small scale problem that they solved. What is small scale and <10K documents / files can be easily processed with grep, find etc. For something at larger scale >1M documents etc. you will need to use search engine technology. You can definitely do the same agent approach for the large scale problem - we essentially need search, look at the results and issue follow up queries to get documents of interest. All that said, for the types of problem the OP is solving, it might just be better to create a project in Claude/ChatGPT and throw in the files there and get done with it. That approach has been working for over 2 years now and is nothing new.