Hardware
Vendors and parts
BOMs, sourcing, and price claims verified like any other claim: against a real listing, a real quote, a real human.
A bill of materials is a stack of claims: that the part exists, at that price, in that quantity, from that seller, compatible with the rest. The machine assembles such stacks fluently, and every line deserves the treatment any claim gets: verification against a live listing, a real quote, or a human who has actually bought one. Component prices remembered from training data are historical fiction with decimal points.
The adversarial ask scales to procurement. Before money moves, task a fresh pass with attacking the BOM: is each part necessary, is that really the price, does a boring alternative do the job. Over-specification hides comfortably in hardware lists, where an exotic line item survives because nobody asked why the ordinary one wouldn't do.
How to practice it
Live listing or it's a rumor.
Every priced line links to where that price currently exists. Remembered prices are wrong in whichever direction hurts.
Attack your own BOM.
A no-stake review of necessity and cost, line by line, before the order. Cheaper than the wrong reel arriving.
Justify the exotic.
Every specialty part answers why the commodity version fails. No answer, no line item.
Verify compatibility in writing.
Footprints, voltages, protocols: checked against both datasheets, not against the phrase 'should work'.