GraphQL - how to filter on custom field

How can you filter a custom field?

Say i have a field in my type definition using @cypher directive:

type Ticket {
id: String
title: String
date: DateTime @cypher(statement: "RETURN datetime(this.timestamp)")

Querying this is fine, however, if I try to filter it:

tickets (where: {date_GT: $from_date}) {

I get "date_GT" is not defined by type "TicketWhere"