What we used to do is exec “fdbcli --exec json” to get the status of the cluster (we basically look at storage queues to decide what to do, since it’ll causes unavailability if they rise too high: 1G for storage server queues and 2G for log server queues).
Thanks to @spullara, apparently you can get the same output just by getting the key \xff\xff/status/json. I was trying hard to get the existing way to work with multi-version clients (and fdbcli is special so it doesn’t work with multi-version clients, per @ajbeamon). This obviously made the dependency to fdbcli obsolete.
Posting here just in case someone finds it useful.