diff --git a/lib/foreman.rb b/lib/foreman.rb
index 63140f9..265d799 100644
--- a/lib/foreman.rb
+++ b/lib/foreman.rb
@@ -2,5 +2,7 @@ module Foreman
 
   VERSION = "0.0.1"
 
+  class AppDoesNotExist < Exception; end
+
 end
 
diff --git a/lib/foreman/cli.rb b/lib/foreman/cli.rb
index 4519209..23dc367 100644
--- a/lib/foreman/cli.rb
+++ b/lib/foreman/cli.rb
@@ -29,7 +29,11 @@ class Foreman::CLI < Thor
   desc "scale APP PROCESS AMOUNT", "Change the concurrency of a given process type"
 
   def scale(app, process, amount)
-    Foreman::Configuration.new(app).scale(process, amount)
+    config = Foreman::Configuration.new(app)
+    error "No such process: #{process}." unless config.processes[process]
+    config.scale(process, amount)
+  rescue Foreman::AppDoesNotExist
+    error "No such app: #{app}."
   end
 
 private ######################################################################
diff --git a/lib/foreman/configuration.rb b/lib/foreman/configuration.rb
index 949c2f5..5479f0a 100644
--- a/lib/foreman/configuration.rb
+++ b/lib/foreman/configuration.rb
@@ -12,7 +12,7 @@ class Foreman::Configuration
   end
 
   def scale(process, amount)
-    old_amount = processes[process]
+    old_amount = processes[process].to_i
     processes[process] = amount.to_i
     amount = amount.to_i
 
@@ -43,6 +43,8 @@ private ######################################################################
     config["#{app}_processes"].split(" ").each do |process|
       processes[process] = config["#{app}_#{process}"].to_i
     end
+  rescue Errno::ENOENT
+    raise Foreman::AppDoesNotExist
   end
 
   def run(command)
diff --git a/spec/foreman/cli_spec.rb b/spec/foreman/cli_spec.rb
index 0641dc0..094e36c 100644
--- a/spec/foreman/cli_spec.rb
+++ b/spec/foreman/cli_spec.rb
@@ -61,15 +61,26 @@ describe "Foreman::CLI" do
 
   describe "scale" do
     describe "without an existing configuration" do
-      # TODO
+      it "displays an error" do
+        mock_error(subject, "No such app: testapp.") do
+          subject.scale("testapp", "alpha", "2")
+        end
+      end
     end
 
     describe "with an existing configuration" do
       before(:each) { write_foreman_config("testapp") }
 
-      it "scales the specified process" do
-        mock.instance_of(Foreman::Configuration).scale("testprocess", "2")
-        subject.scale("testapp", "testprocess", "2")
+      it "scales a process that exists" do
+        mock.instance_of(Foreman::Configuration).scale("alpha", "2")
+        subject.scale("testapp", "alpha", "2")
+      end
+
+      it "errors if a process that does not exist is specified" do
+        mock_error(subject, "No such process: invalidprocess.") do
+          dont_allow.instance_of(Foreman::Configuration).scale
+          subject.scale("testapp", "invalidprocess", "2")
+        end
       end
     end
   end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index afa5f75..2c4b9c8 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -3,19 +3,6 @@ require "rspec"
 
 $:.unshift "lib"
 
-# def stub_configuration
-#   config = mock(Foreman::Configuration)
-#   Foreman::Configuration.stub(:new).and_return(config)
-#   config  
-# end
-# 
-# 
-# def stub_export_upstart
-#   upstart = mock(Foreman::Export::Upstart)
-#   Foreman::Export::Upstart.stub(:new).and_return(upstart)
-#   upstart
-# end
-
 def mock_error(subject, message)
   mock_exit do
     mock(subject).puts("ERROR: #{message}")
@@ -27,17 +14,11 @@ def mock_exit(&block)
   block.should raise_error(SystemExit)
 end
 
-# def stub_engine
-#   engine = mock(Foreman::Engine)
-#   stub(Foreman::Engine).new { engine }
-#   engine
-# end
-# 
 def write_foreman_config(app)
   File.open("/etc/foreman/#{app}.conf", "w") do |file|
     file.puts %{#{app}_processes="alpha bravo"}
     file.puts %{#{app}_alpha="1"}
-    file.puts %{#{app}_bravo="2"}    
+    file.puts %{#{app}_bravo="2"}
   end
 end