Even with GPT-5: Why can’t I get long outputs like 20-page PDFs?

Hey 👋 I’ve been testing GPT-5 and ran into what feels like a frustrating limitation.

Even with the newest model, it still seems impossible to do something like:

• Upload a 20-page PDF,
• Ask: “Translate this into Spanish, keep exactly the same formatting, and give me the output as a PDF”,
• Or: “Create a very extensive document, like 15–20 pages, with full detail and structure”.

I’m not talking about reading or processing large documents — that part works fine.
I’m talking about output length and file generation.

Whenever I try, GPT stops after a few pages worth of text. It just won’t produce a full-length document in one go, even though the task is completely clear. This means I have to manually ask “Continue” again and again, then stitch everything together — which defeats the purpose.

Questions:

1. Is this still a hard technical limit in GPT-5 regarding output size for PDFs and long-form text generation?
2. Is there a right way to prompt it so that it will actually produce a massive, multi-page output in a single pass?
3. Has anyone found a workflow (e.g., chunking, specialized prompting, or API settings) that works reliably for this kind of long output?

I’m looking for a method to make GPT produce something very extensive (tens of pages) as a finished file, without me having to babysit the process.