> cat orders.yaml
primary_keys: [order_id]
source:
  path: legacy.csv
target:
  path: modern.csv
> head -n 2 legacy.csv
id,status,amount
1,open,10.0
> veridelta validate -c orders.yaml --schemas
error: The primary key 'order_id' is not among the columns of the source, `legacy.csv` read as csv. The columns read are: 'id', 'status', 'amount'.
orders.yaml: 1 error, 0 warnings.
> echo "exit code: $?"
exit code: 1
