diff --git a/lib/inferno/apps/cli/evaluate.rb b/lib/inferno/apps/cli/evaluate.rb
index 555832a1d..7d0ded97e 100644
--- a/lib/inferno/apps/cli/evaluate.rb
+++ b/lib/inferno/apps/cli/evaluate.rb
@@ -1,14 +1,30 @@
 require_relative '../../../inferno/dsl/fhir_evaluation/evaluator'
+require_relative '../../../inferno/dsl/fhir_evaluation/config'
+require_relative '../../../inferno/dsl/ig'
+require_relative '../../utils/ig_downloader'
+
+require 'tempfile'
 
 module Inferno
   module CLI
-    class Evaluate
-      def run(ig_path, data_path, _log_level)
+    class Evaluate < Thor::Group
+      include Thor::Actions
+      include Inferno::Utils::IgDownloader
+
+      def evaluate(ig_path, data_path, _log_level)
         validate_args(ig_path, data_path)
 
-        # IG Import, rule execution, and result output below will be integrated at phase 2 and 3.
+        if File.file?(ig_path)
+          ig = Inferno::DSL::IG.from_file(ig_path)
+        else
+          Tempfile.create('package.tgz') do |temp_file|
+            load_ig(ig_path, nil, { force: true }, temp_file.path)
+            ig = Inferno::DSL::IG.from_file(temp_file.path)
+          end
+        end
+
+        # Rule execution, and result output below will be integrated at phase 2 and 3.
 
-        # @ig = File.join(__dir__, 'ig', ig_path)
         # if data_path
         #   DatasetLoader.from_path(File.join(__dir__, data_path))
         # else
diff --git a/lib/inferno/apps/cli/main.rb b/lib/inferno/apps/cli/main.rb
index fdcdb4cdc..0e5e9b2ed 100644
--- a/lib/inferno/apps/cli/main.rb
+++ b/lib/inferno/apps/cli/main.rb
@@ -45,7 +45,7 @@ class Main < Thor
              type: :string,
              desc: 'Export evaluation result to outcome.json as an OperationOutcome'
       def evaluate(ig_path)
-        Evaluate.new.run(ig_path, options[:data_path], Logger::INFO)
+        Evaluate.new.evaluate(ig_path, options[:data_path], Logger::INFO)
       end
 
       desc 'console', 'Start an interactive console session with Inferno'
diff --git a/lib/inferno/dsl/ig.rb b/lib/inferno/dsl/ig.rb
new file mode 100644
index 000000000..cd767b467
--- /dev/null
+++ b/lib/inferno/dsl/ig.rb
@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+require 'fhir_models'
+require 'rubygems/package'
+require 'zlib'
+
+module Inferno
+  module DSL
+    # IG is a wrapper class around the relevant concepts inside an IG.
+    # Not everything within an IG is currently used by Inferno.
+    class IG
+      attr_accessor :profiles, :extensions, :value_sets, :search_params, :examples
+
+      def initialize
+        @profiles = []
+        @extensions = []
+        @value_sets = []
+        @examples = []
+        @search_params = []
+      end
+
+      def self.from_file(ig_path)
+        raise "#{ig_path} is not an IG file" unless File.file?(ig_path)
+
+        tar = Gem::Package::TarReader.new(
+          Zlib::GzipReader.open(ig_path)
+        )
+
+        # fhir_models by default logs the entire content of non-FHIR files
+        # which could be things like a package.json
+        original_logger = FHIR.logger
+        FHIR.logger = Logger.new('/dev/null')
+
+        ig = IG.new
+
+        tar.each do |entry|
+          next if skip_tar_entry? entry
+
+          begin
+            resource = FHIR::Json.from_json(entry.read)
+            next if resource.nil?
+
+            ig.add_resource(resource, entry)
+          rescue StandardError
+            next
+          end
+        end
+
+        ig
+      ensure
+        FHIR.logger = original_logger if defined? original_logger
+      end
+
+      # These files aren't FHIR resources
+      FILES_TO_SKIP = ['package.json', 'validation-summary.json'].freeze
+
+      def self.skip_tar_entry?(entry)
+        return true if entry.directory?
+
+        file_name = entry.full_name.split('/').last
+
+        # TODO: consider making these regexes we can iterate over in a single loop
+        return true unless file_name.end_with? '.json'
+        return true unless entry.full_name.start_with? 'package/'
+
+        return true if file_name.start_with? '.' # ignore hidden files
+        return true if file_name.end_with? '.openapi.json'
+        return true if FILES_TO_SKIP.include? file_name
+
+        false
+      end
+
+      def add_resource(resource, entry)
+        if resource.resourceType == 'StructureDefinition'
+          if resource.type == 'Extension'
+            extensions.push resource
+          else
+            profiles.push resource
+          end
+        elsif resource.resourceType == 'ValueSet'
+          value_sets.push resource
+        elsif resource.resourceType == 'SearchParameter'
+          search_params.push resource
+        elsif entry.full_name.start_with? 'package/example'
+          examples.push resource
+        end
+      end
+    end
+  end
+end
diff --git a/lib/inferno/utils/ig_downloader.rb b/lib/inferno/utils/ig_downloader.rb
index 2f2ff9be3..f9acd0bff 100644
--- a/lib/inferno/utils/ig_downloader.rb
+++ b/lib/inferno/utils/ig_downloader.rb
@@ -14,7 +14,7 @@ def ig_file(suffix = nil)
         File.join(ig_path, suffix ? "package_#{suffix}.tgz" : 'package.tgz')
       end
 
-      def load_ig(ig_input, idx = nil, thor_config = { verbose: true })
+      def load_ig(ig_input, idx = nil, thor_config = { verbose: true }, output_path = nil)
         case ig_input
         when FHIR_PACKAGE_NAME_REG_EX
           uri = ig_registry_url(ig_input)
@@ -29,8 +29,9 @@ def load_ig(ig_input, idx = nil, thor_config = { verbose: true })
           FAILED_TO_LOAD
         end
 
+        destination = output_path || ig_file(idx)
         # use Thor's get to support CLI options config
-        get(uri, ig_file(idx), thor_config)
+        get(uri, destination, thor_config)
         uri
       end