How to reliably analyze larger PDFs (60–80 pages) with GPT in Zapier?

Hi everyone,

we’re currently facing a challenge in automating the analysis of larger PDF documents (60–80 pages) using GPT in Zapier.

👉 Our use case: We want to check formal criteria in documents like real estate reports, such as:

This works well when uploading the PDF directly into ChatGPT via the web app – the model can identify these elements with a good degree of accuracy.

However, when using Zapier, we’re running into two major issues:

The full PDF (especially longer files) often cannot be parsed or passed to GPT reliably.
Even when passing specific text excerpts (e.g., page 1 or the last page), GPT in Zapier tends to hallucinate results rather than strictly confirming whether a signature or cover page is truly present.

❓ What we’re looking for:

What’s the best way to extract and structure PDF contents for reliable GPT analysis in Zapier, Make, or n8n?
Which tools (PDF parsers, converters, etc.) are working well in your setup?
Any best practices for feeding GPT only key pages (e.g., cover and signature pages)?
How do you manage GPT’s context limits in these automation platforms?

We would really appreciate any technical advice, workflows, or tools you’ve found to solve this!

Thanks a lot in advance,

Niklas

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