graphql-php/src/Server/RequestError.php

<?php
namespace GraphQL\Server;

use GraphQL\Error\ClientAware;

class RequestError extends \Exception implements ClientAware
{
    /**
     * Returns true when exception message is safe to be displayed to client
     *
     * @return bool
     */
    public function isClientSafe()
    {
        return true;
    }

    /**
     * Returns string describing error category. E.g. "validation" for your own validation errors.
     *
     * Value "graphql" is reserved for errors produced by query parsing or validation, do not use it.
     *
     * @return string
     */
    public function getCategory()
    {
        return 'request';
    }
}