From IMG_4382.jpg to Invoice_Acme_2024-03.pdf: Building a Content-Aware Renaming Pipeline

Plug in a flatbed scanner and watch what happens to your filenames. Every document gets named Scan0047.pdf . Photos leave the camera as IMG_4382.jpg . Screenshots pile up as Screenshot 2024-03-14 at 09.42.17.png . Within a week, a Downloads folder turns into a graveyard of meaningless names attached to files that might be anything. The naive fix is a renaming rule. "Anything prefixed with Scan goes into /documents/scans/ ." That works until your scanner firmware updates and starts outputting IMG prefixes. Or until you add a second scanner. Rule-based approaches collapse because they operate on filenames, and filenames carry exactly zero semantic information about what's inside the file. This post walks through the engineering approach we use to solve this: a content-aware renaming pipeline that reads the document, understands what it is, and generates a meaningful name from the content itself. Why filename metadata is a dead end Before getting into the solution, it helps to be precise