The CSV reader should take a schema argument to handle cases where there is no CSV header in the file but simply a sequence of comma-separated values. The schema would simply be a ZSON record type passed as a command-line arg to on the input flags group.

For example,

echo '1,"foo"' | zq  -i csv -schema '{a:int64,b:string}' -

would produce

{a:1,b:"foo"}

Thanks to Jason Deyalsingh for suggesting this on Brim slack.