Fair point. Databases encoding queries in JSON get some error messages for free, at least when it comes to "syntax". But I think even others do well.

I just logged into Grafana and tried writing a simple query. Upon failing I got a reasonably detailed and specific error message: 'parse error: expected type range vector in call to function "rate", got instant vector'.

I also tried XQuery in Xidel and it gave me nicely descriptive responses to whichever mistakes I introduced.