The current API docs say to use: https://github.com/fleetdm/fleet/blob/master/docs/1-Using-Fleet/3-REST-API.md#example-with-one-host-targeted-by-id But

/spec/

is not currently used in the Fleet API - is this future or just an oversight in the docs?

This is a mistake in the docs. The correct endpoint is

/api/v1/fleet/queries/run

with no

/spec/