diff --git a/Gemfile.lock b/Gemfile.lock
index cb0e14c..987133c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,10 +2,23 @@ PATH
   remote: .
   specs:
     coursemology-evaluator (0.0.0)
+      active_rest_client (~> 1.2)
+      activesupport (~> 4.2.0)
 
 GEM
   remote: https://rubygems.org/
   specs:
+    active_rest_client (1.2.0)
+      activesupport
+      crack
+      faraday
+      multi_json
+    activesupport (4.2.5)
+      i18n (~> 0.7)
+      json (~> 1.7, >= 1.7.7)
+      minitest (~> 5.1)
+      thread_safe (~> 0.3, >= 0.3.4)
+      tzinfo (~> 1.1)
     codeclimate-test-reporter (0.4.8)
       simplecov (>= 0.7.1, < 1.0.0)
     coveralls (0.8.10)
@@ -15,14 +28,22 @@ GEM
       term-ansicolor (~> 1.3)
       thor (~> 0.19.1)
       tins (~> 1.6.0)
+    crack (0.4.3)
+      safe_yaml (~> 1.0.0)
     diff-lcs (1.2.5)
     docile (1.1.5)
     domain_name (0.5.25)
       unf (>= 0.0.5, < 1.0.0)
+    faraday (0.9.2)
+      multipart-post (>= 1.2, < 3)
     http-cookie (1.0.2)
       domain_name (~> 0.5)
+    i18n (0.7.0)
     json (1.8.3)
     mime-types (2.99)
+    minitest (5.8.3)
+    multi_json (1.11.2)
+    multipart-post (2.0.0)
     netrc (0.11.0)
     rake (10.4.2)
     rest-client (1.8.0)
@@ -42,6 +63,7 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.4.0)
     rspec-support (3.4.1)
+    safe_yaml (1.0.4)
     simplecov (0.11.1)
       docile (~> 1.1.0)
       json (~> 1.8)
@@ -50,7 +72,10 @@ GEM
     term-ansicolor (1.3.2)
       tins (~> 1.0)
     thor (0.19.1)
+    thread_safe (0.3.5)
     tins (1.6.0)
+    tzinfo (1.2.2)
+      thread_safe (~> 0.1)
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.1)
diff --git a/bin/evaluator b/bin/evaluator
new file mode 100644
index 0000000..65bf7fd
--- /dev/null
+++ b/bin/evaluator
@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+require 'bundler/setup'
+require 'coursemology/evaluator'
+
+Coursemology::Evaluator::CLI.start(ARGV)
diff --git a/coursemology-evaluator.gemspec b/coursemology-evaluator.gemspec
index c217775..115f546 100644
--- a/coursemology-evaluator.gemspec
+++ b/coursemology-evaluator.gemspec
@@ -24,4 +24,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'simplecov'
   spec.add_development_dependency 'coveralls'
   spec.add_development_dependency 'codeclimate-test-reporter'
+
+  spec.add_dependency 'activesupport', '~> 4.2.0'
+  spec.add_dependency 'active_rest_client', '~> 1.2'
 end
diff --git a/lib/coursemology/evaluator.rb b/lib/coursemology/evaluator.rb
index 406384e..6cb6283 100644
--- a/lib/coursemology/evaluator.rb
+++ b/lib/coursemology/evaluator.rb
@@ -1,7 +1,11 @@
+require 'active_support/all'
+require 'active_rest_client'
 require 'coursemology/evaluator/version'
 
-module Coursemology
-  module Evaluator
-    # Your code goes here...
-  end
+module Coursemology::Evaluator
+  extend ActiveSupport::Autoload
+
+  autoload :Client
+  autoload :CLI
+  autoload :Models
 end
diff --git a/lib/coursemology/evaluator/cli.rb b/lib/coursemology/evaluator/cli.rb
new file mode 100644
index 0000000..30e7f46
--- /dev/null
+++ b/lib/coursemology/evaluator/cli.rb
@@ -0,0 +1,47 @@
+require 'optparse'
+
+class Coursemology::Evaluator::CLI
+  Options = Struct.new(:host, :api_token, :api_user_email)
+
+  def self.start(argv)
+    new.start(argv)
+  end
+
+  def start(argv)
+    run(argv)
+  end
+
+  def run(argv)
+    options = optparse!(argv)
+    Coursemology::Evaluator::Client.initialize(options.host, options.api_user_email,
+                                               options.api_token)
+    Coursemology::Evaluator::Client.new.run
+  end
+
+  private
+
+  # Parses the options specified on the command line.
+  #
+  # @param [Array<String>] argv The arguments specified on the command line.
+  # @return [Coursemology::Evaluator::CLI::Options]
+  def optparse!(argv) # rubocop:disable Metrics/MethodLength
+    options = Options.new
+    option_parser = OptionParser.new do |parser|
+      parser.banner = "Usage: #{parser.program_name} [options]"
+      parser.on('-hHOST', '--host=HOST', 'Coursemology host to connect to') do |host|
+        options.host = host
+      end
+
+      parser.on('-tTOKEN', '--api-token=TOKEN') do |token|
+        options.api_token = token
+      end
+
+      parser.on('-uUSER', '--api-user-email=USER') do |user|
+        options.api_user_email = user
+      end
+    end
+
+    option_parser.parse!(argv)
+    options
+  end
+end
diff --git a/lib/coursemology/evaluator/client.rb b/lib/coursemology/evaluator/client.rb
new file mode 100644
index 0000000..df59822
--- /dev/null
+++ b/lib/coursemology/evaluator/client.rb
@@ -0,0 +1,13 @@
+class Coursemology::Evaluator::Client
+  def self.initialize(host, api_user_email, api_token)
+    Coursemology::Evaluator::Models::Base.base_url = host
+    Coursemology::Evaluator::Models::Base.api_user_email = api_user_email
+    Coursemology::Evaluator::Models::Base.api_token = api_token
+  end
+
+  def initialize
+  end
+
+  def run
+  end
+end
diff --git a/lib/coursemology/evaluator/models.rb b/lib/coursemology/evaluator/models.rb
new file mode 100644
index 0000000..80b24ce
--- /dev/null
+++ b/lib/coursemology/evaluator/models.rb
@@ -0,0 +1,6 @@
+module Coursemology::Evaluator::Models
+  extend ActiveSupport::Autoload
+
+  autoload :Base
+  autoload :ProgrammingEvaluation
+end
diff --git a/lib/coursemology/evaluator/models/base.rb b/lib/coursemology/evaluator/models/base.rb
new file mode 100644
index 0000000..457c48c
--- /dev/null
+++ b/lib/coursemology/evaluator/models/base.rb
@@ -0,0 +1,16 @@
+class Coursemology::Evaluator::Models::Base < ActiveRestClient::Base
+  class << self
+    attr_accessor :api_user_email
+    attr_accessor :api_token
+  end
+
+  before_request :add_authentication
+
+  private
+
+  # Adds the authentication email and token to the request.
+  def add_authentication(_, request)
+    request.headers['X-User-Email'] = self.class.api_user_email
+    request.headers['X-User-Token'] = self.class.api_token
+  end
+end
diff --git a/spec/coursemology/evaluator/cli_spec.rb b/spec/coursemology/evaluator/cli_spec.rb
new file mode 100644
index 0000000..bccb8d5
--- /dev/null
+++ b/spec/coursemology/evaluator/cli_spec.rb
@@ -0,0 +1,60 @@
+RSpec.describe Coursemology::Evaluator::CLI do
+  let(:host) { 'http://localhost:3000' }
+  let(:api_token) { 'abcd' }
+  let(:api_user_email) { 'test@example.org' }
+  let(:argv) do
+    ["--host=#{host}", "--api-token=#{api_token}", "--api-user-email=#{api_user_email}"]
+  end
+
+  describe Coursemology::Evaluator::CLI::Options do
+    it { is_expected.to have_attributes(host: nil, api_token: nil, api_user_email: nil) }
+  end
+
+  with_mock_client do
+    describe '.start' do
+      subject { Coursemology::Evaluator::CLI }
+      it 'calls #start' do
+        expect(subject).to receive_message_chain(:new, :start)
+        subject.start(argv)
+      end
+    end
+
+    describe '#start' do
+      subject { Coursemology::Evaluator::CLI.new }
+      it 'calls #run' do
+        expect(subject).to receive(:run).and_call_original
+        subject.start(argv)
+      end
+    end
+
+    describe '#run' do
+      subject { Coursemology::Evaluator::CLI.new.run(argv) }
+
+      it 'creates a client' do
+        expect(Coursemology::Evaluator::Client).to receive(:new).and_call_original
+        subject
+      end
+
+      it 'runs the client' do
+        expect(Coursemology::Evaluator::Client).to receive_message_chain(:new, :run)
+        subject
+      end
+    end
+  end
+
+  describe '#optparse!' do
+    subject { Coursemology::Evaluator::CLI.new.send(:optparse!, argv) }
+
+    it 'parses --host' do
+      expect(subject.host).to eq(host)
+    end
+
+    it 'parses --api-token' do
+      expect(subject.api_token).to eq(api_token)
+    end
+
+    it 'parses api-user-email' do
+      expect(subject.api_user_email).to eq(api_user_email)
+    end
+  end
+end
diff --git a/spec/coursemology/evaluator/client_spec.rb b/spec/coursemology/evaluator/client_spec.rb
new file mode 100644
index 0000000..c28fd89
--- /dev/null
+++ b/spec/coursemology/evaluator/client_spec.rb
@@ -0,0 +1,18 @@
+RSpec.describe Coursemology::Evaluator::Client do
+  with_mock_client do
+    describe '.initialize' do
+      let(:base_url) { 'http://localhost:3000' }
+      let(:api_token) { 'abcd' }
+      let(:api_user_email) { 'test@example.org' }
+
+      subject { Coursemology::Evaluator::Client }
+
+      it 'sets the API parameters' do
+        subject.initialize(base_url, api_user_email, api_token)
+        expect(Coursemology::Evaluator::Models::Base.base_url).to eq(base_url)
+        expect(Coursemology::Evaluator::Models::Base.api_user_email).to eq(api_user_email)
+        expect(Coursemology::Evaluator::Models::Base.api_token).to eq(api_token)
+      end
+    end
+  end
+end
diff --git a/spec/coursemology/evaluator/models/base_spec.rb b/spec/coursemology/evaluator/models/base_spec.rb
new file mode 100644
index 0000000..abb75f3
--- /dev/null
+++ b/spec/coursemology/evaluator/models/base_spec.rb
@@ -0,0 +1,37 @@
+RSpec.describe Coursemology::Evaluator::Models::Base do
+  describe 'class attributes' do
+    subject { Coursemology::Evaluator::Models::Base }
+
+    describe '.api_user_email' do
+      it { is_expected.to have_attributes(api_user_email: nil) }
+    end
+
+    describe '.api_token' do
+      it { is_expected.to have_attributes(api_token: nil) }
+    end
+  end
+
+  describe '#adds_authentication' do
+    with_mock_client(api_user_email: 'email', api_token: 'token') do
+      let(:request) do
+        headers = {}
+        double.tap do |double|
+          expect(double).to receive(:headers).and_return(headers).at_least(:once)
+        end
+      end
+      subject { Coursemology::Evaluator::Models::Base.new.send(:add_authentication, nil, request) }
+
+      it 'adds the X-User-Email header' do
+        subject
+        expect(request.headers['X-User-Email']).to \
+          eq(Coursemology::Evaluator::Models::Base.api_user_email)
+      end
+
+      it 'adds the X-User-Token header' do
+        subject
+        expect(request.headers['X-User-Token']).to \
+          eq(Coursemology::Evaluator::Models::Base.api_token)
+      end
+    end
+  end
+end
diff --git a/spec/coursemology/evaluator_spec.rb b/spec/coursemology/evaluator_spec.rb
index 4308148..4bcbc94 100644
--- a/spec/coursemology/evaluator_spec.rb
+++ b/spec/coursemology/evaluator_spec.rb
@@ -4,8 +4,4 @@
   it 'has a version number' do
     expect(Coursemology::Evaluator::VERSION).not_to be nil
   end
-
-  it 'does something useful' do
-    expect(false).to eq(true)
-  end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 54af732..07b9dc9 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -19,6 +19,7 @@
 $LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)
 require 'coverage_helper'
 require 'coursemology/evaluator'
+Dir["#{__dir__}/support/**/*"].each { |file| require file }
 
 RSpec.configure do |config|
   # rspec-expectations config goes here. You can use an alternate
diff --git a/spec/support/client_stub.rb b/spec/support/client_stub.rb
new file mode 100644
index 0000000..accac39
--- /dev/null
+++ b/spec/support/client_stub.rb
@@ -0,0 +1,50 @@
+class Coursemology::Evaluator::Client
+  module TestGroupHelperMethods
+    def self.client_options_description(host, api_user_email, api_token)
+      result = []
+      result << "host: #{host}" if host
+      result << "api_user_email: #{api_user_email}" if api_user_email
+      result << "api_token: #{api_token}" if api_token
+
+      result
+    end
+
+    def self.mock_client(host, api_user_email, api_token)
+      proc do
+        base_model = Coursemology::Evaluator::Models::Base
+        instance_exec(base_model, :base_url, host,
+                      &TestGroupHelperMethods.instance_method(:mock_property).bind(self))
+        instance_exec(base_model, :api_user_email, api_user_email,
+                      &TestGroupHelperMethods.instance_method(:mock_property).bind(self))
+        instance_exec(base_model, :api_token, api_token,
+                      &TestGroupHelperMethods.instance_method(:mock_property).bind(self))
+      end
+    end
+
+    def mock_property(object, property, value)
+      allow(object).to receive(property) do
+        value
+      end
+      allow(object).to receive("#{property}=".to_s) do |new_value|
+        value = new_value
+      end
+    end
+  end
+
+  module TestGroupHelpers
+    def with_mock_client(host: nil, api_user_email: nil, api_token: nil, &block)
+      client_description = TestGroupHelperMethods.
+                           client_options_description(host, api_user_email, api_token).to_sentence
+
+      context "with client: #{client_description}" do
+        before(:each, &TestGroupHelperMethods.mock_client(host, api_user_email, api_token))
+
+        module_eval(&block)
+      end
+    end
+  end
+end
+
+RSpec.configure do |config|
+  config.extend Coursemology::Evaluator::Client::TestGroupHelpers
+end