The build manifest records every dependency resolved inside the vendor's isolated registry. Those resolutions never survive contact with the buyer's actual registry policies and rate limits.
When the same package lands in your environment, pinned versions collide with corporate mirrors that strip unsigned packages and enforce newer minimums. The product stalls before any user sees it.
Buy decisions made on demo walkthroughs skip this step entirely. The vendor never ships the manifest for pre-flight review, so procurement treats the binary as the deliverable.
Real craft shows up in repeatable build instructions that survive your security scans and your network constraints. Strategy decks never include those instructions.
Teams that insist on a reproducible build artifact before signing catch the drift early. They force the vendor to publish the exact lockfile and rebuild it under observation.
The alternative is endless post-purchase patches that turn the purchase into a custom development project at full rate card. Build versus buy stops being a choice once the manifest stays hidden.
Demand the manifest and the rebuild test as part of any product evaluation. Anything less leaves the real integration work for your own people after the contract is locked.