Mongoid wraps the Driver handshake metadata already and appends runtime details to the platform field (ex: mongoid-7.0.13, JRuby 9.3.15.0, like Ruby 2.6.8, java, JVM 17.0.15, java1.8, M).
Given it's very likely Mongoid is being used from within Ruby on Rails, it would be worth capturing the current framework version and appending this to the handshake on client instantiation (ex: "Rails #{Rails.try(:version)}" if defined?(Rails))