diff --git a/Gemfile b/Gemfile
index a7a40d797..3c4aa8c94 100644
--- a/Gemfile
+++ b/Gemfile
@@ -21,6 +21,7 @@ group :development do
   gem 'rmail', '~> 1.1'
   gem 'sinatra', '~> 1.4'
   gem 'redis', '~> 3.2'
+  gem 'activesupport', '>= 3.2'
 end
 
 platforms :jruby do
diff --git a/bin/generate-api b/bin/generate-api
index c16b6f957..f9a8111e6 100755
--- a/bin/generate-api
+++ b/bin/generate-api
@@ -1,15 +1,17 @@
 #!/usr/bin/env ruby
 
-# TODO - Repeated params
-
 require 'thor'
 require 'open-uri'
 require 'google/apis/discovery_v1'
-require 'google/apis/generator'
 require 'logger'
 
 module Google
   class ApiGenerator < Thor
+
+    def self.exit_on_failure?
+      true
+    end
+
     include Thor::Actions
 
     Google::Apis::ClientOptions.default.application_name = "generate-api"
@@ -23,6 +25,9 @@ module Google
                    names_out: :string
     method_option :preferred_only, default: true
     def gen(dir)
+      ensure_active_support
+      require 'google/apis/generator'
+
       self.destination_root = dir
       Google::Apis.logger.level = Logger::DEBUG if options[:verbose]
       generate_from_url(options[:url]) if options[:url]
@@ -86,6 +91,16 @@ module Google
       def generator
         @generator ||= Google::Apis::Generator.new(api_names: options[:names])
       end
+
+      def ensure_active_support
+        begin
+          require 'active_support/inflector'
+        rescue LoadError => e
+          error 'ActiveSupport is required, please run:'
+          error 'gem install activesupport'
+          exit 1
+        end
+      end
     end
   end
 
diff --git a/lib/google/apis/core/api_command.rb b/lib/google/apis/core/api_command.rb
index 2733ae13c..519c0c97e 100644
--- a/lib/google/apis/core/api_command.rb
+++ b/lib/google/apis/core/api_command.rb
@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-require 'active_support/inflector'
 require 'addressable/uri'
 require 'addressable/template'
 require 'google/apis/core/http_command'
@@ -127,7 +126,9 @@ module Google
         #   Updated header value
         def normalize_fields_param(fields)
           # TODO: Generate map of parameter names during code gen. Small possibility that camelization fails
-          fields.gsub(/:/, '').gsub(/\w+/) { |str| ActiveSupport::Inflector.camelize(str, false) }
+          fields.gsub(/:/, '').gsub(/\w+/) do |str|
+            str.gsub(/(?:^|_)([a-z])/){ Regexp.last_match.begin(0) == 0 ? $1 : $1.upcase }
+          end
         end
       end
     end
diff --git a/spec/google/apis/core/api_command_spec.rb b/spec/google/apis/core/api_command_spec.rb
index bcbc896e8..4920c496c 100644
--- a/spec/google/apis/core/api_command_spec.rb
+++ b/spec/google/apis/core/api_command_spec.rb
@@ -103,7 +103,7 @@ RSpec.describe Google::Apis::Core::HttpCommand do
   context('with a field parameter') do
     let(:command) do
       command = Google::Apis::Core::ApiCommand.new(:get, 'https://www.googleapis.com/zoo/animals')
-      command.query['fields'] = ':items(:id, :long_name)'
+      command.query['fields'] = ':items(:id, :long_name, :a_really_long_name), shouldBeLeftAlone '
       command
     end
 
@@ -115,7 +115,7 @@ RSpec.describe Google::Apis::Core::HttpCommand do
     it 'should normalize fields params' do
       command.execute(client)
       expect(a_request(:get, 'https://www.googleapis.com/zoo/animals')
-        .with(query: { 'fields' => 'items(id, longName)' })) .to have_been_made
+        .with(query: { 'fields' => 'items(id, longName, aReallyLongName), shouldBeLeftAlone ' })) .to have_been_made
     end
   end