PDF chat
PDF chat refers to the workflow of uploading a PDF document and querying its contents through a language model interface. The model parses the PDF, indexes its text, and answers questions grounded in the document, ideally with citations back to specific pages.
PDF chat tools differ in three important dimensions: how they parse the PDF (text extraction quality affects citation accuracy), how they chunk and retrieve passages (affects answer completeness on long documents), and whether they expose citations to the user (affects verifiability).
For multi-document research, single-PDF chat hits a ceiling quickly. The next step up is multi-document workspaces that let you query across many PDFs while preserving per-document citations, this is where Atlas, NotebookLM, and Claude Projects diverge from ChatPDF and similar single-file tools.
When evaluating PDF chat tools, test them on a paper with figures, tables, and equations, those are the formats where extraction quality varies most.