Comment by ndr_

It's a fallacy to believe that ChatGPT or Claude would look at some encoded, unfit for the purpose, text representation. ChatGPT (and the OpenAI Responses API, I believe) in particular renders the PDF pages in addition to text extraction, so the whole premise of "But now most PDFs end up in an LLM" is wrong from the start. If you were to be processing PDFs in a pure LLM stage, there are options like Docling or LlamaParse for proper preprocessing.