Thanks, that works. I can put something simple in my settings.json like this

  "debugVisualizer.debugAdapterConfigurations": {
    "Ruby": {
      "expressionTemplate": "DataExtractor.to_table(${expr})",
    }
   },

..and something simple in the debugee like this..

  table_example = 
    {"id"=> "1", "label"=> "One"},
    {"id"=> "2", "label"=> "Two"},
    {"id"=> "3", "label"=> "Three"}
  
  # Quick hash to visual table helper
  class DataExtractor
    def self.to_table(hash)
      meta_hash = {
        "kind" => {"table"=> true},
        "rows"=> hash
      }
      meta_hash.to_json
    end
  end

..and we get a decent hash or ActiveRecord visualizer. Thanks for the hint.