A close pipeline that refuses bad numbers
A multi-entity, international insurance company closed its books through a manual cycle: export the general ledger, convert currencies, stage, load, and hope nothing slipped. The hard part wasn't the automation. It was that the output feeds audited financials, so a fast pipeline that could load a wrong number would be worse than a slow one.
I replaced the cycle with a single command, then built the part that matters: a tie-out gate that blocks any load off by more than $10,000 per entity, and vendor classification where a person approves or rejects every new mapping before the system learns it.
The control: the pipeline stops itself. Bad loads are blocked, they don't wait for someone to notice. The company's name stays private; the figures were checked against its books.