Before any record moves, the definition of the audience is agreed. The build is repeatable, because the rules are written rather than remembered. Nothing is enriched from a source that cannot be named.
Mailbox shape
Distinguishing an individual's address from a shared or departmental one before either is used.
Classification check
Verifying categories against the underlying description rather than trusting a label applied upstream.
Row-count assertion
Checking the delivered file holds the number of rows the summary claims it holds.
Tell us the criteria and we will tell you the count, at no cost either way.