Map the hand-offs before you pick a tool
Who starts the task, where the file arrives, which field is retyped, where the result must land, and what a failure looks like. Until that is on one page, n8n, a custom worker or an AI extractor are guesses.
Hard fields stay in code and APIs: amounts, VAT IDs, order statuses, retry counters. Language and messy documents are the only place a model earns a seat. A single prompt that "does the process" is the architecture we refuse.