The PDF That Passed the Demo Is Not the PDF That Breaks Production PDF processing looks solved until users upload real PDFs. The demo file is usually clean. It has selectable text, simple pages, predictable fonts, and a layout that behaves like the sample in the docs. The extraction library returns text. The document parser finds the invoice number. The generated report looks right. Everyone agrees the pipeline works. Then production traffic starts. One customer uploads a scanned PDF with no text layer. Another uploads a digitally generated PDF where the text order does not match the visual order. A supplier sends a password-protected file. A table splits across pages. A contract has rotated annex pages. A report generator fails because the extracted value was not a value at all, just a footer repeated on every page. The pipeline did not fail because PDFs are impossible. It failed because the workflow treated PDF processing as one operation instead of a sequence of uncertain states.…