diff --git a/bin/run-loop b/bin/run-loop
index 3a24379f..d6a1f425 100755
--- a/bin/run-loop
+++ b/bin/run-loop
@@ -1,11 +1,12 @@
 #!/usr/bin/env ruby
 require 'run_loop/cli/cli'
+require 'run_loop/cli/errors'
 require 'run_loop/environment'
 
 begin
   RunLoop::CLI::Tool.start
   exit 0
-rescue RunLoop::ValidationError, Thor::RequiredArgumentMissingError, Thor::UndefinedCommandError => e
+rescue RunLoop::CLI::ValidationError, Thor::RequiredArgumentMissingError, Thor::UndefinedCommandError => e
   puts e.message
   exit 64
 rescue Thor::Error => e
diff --git a/lib/run_loop/cli/cli.rb b/lib/run_loop/cli/cli.rb
index 89a8d794..6539c700 100644
--- a/lib/run_loop/cli/cli.rb
+++ b/lib/run_loop/cli/cli.rb
@@ -1,5 +1,6 @@
 require 'thor'
 require 'run_loop'
+require 'run_loop/cli/errors'
 require 'run_loop/cli/instruments'
 
 trap 'SIGINT' do
@@ -8,8 +9,6 @@
 end
 
 module RunLoop
-  class ValidationError < Thor::InvocationError
-  end
 
   module CLI
 
diff --git a/lib/run_loop/cli/errors.rb b/lib/run_loop/cli/errors.rb
new file mode 100644
index 00000000..0b78bc16
--- /dev/null
+++ b/lib/run_loop/cli/errors.rb
@@ -0,0 +1,11 @@
+require 'thor'
+
+module RunLoop
+  module CLI
+    class ValidationError < Thor::InvocationError
+    end
+
+    class NotImplementedError < Thor::InvocationError
+    end
+  end
+end
diff --git a/lib/run_loop/cli/instruments.rb b/lib/run_loop/cli/instruments.rb
index a5ec1483..15379bba 100644
--- a/lib/run_loop/cli/instruments.rb
+++ b/lib/run_loop/cli/instruments.rb
@@ -1,5 +1,6 @@
 require 'thor'
 require 'run_loop'
+require 'run_loop/cli/errors'
 
 module RunLoop
   module CLI
diff --git a/spec/lib/bin/errors_spec.rb b/spec/lib/bin/errors_spec.rb
new file mode 100644
index 00000000..cdcaba80
--- /dev/null
+++ b/spec/lib/bin/errors_spec.rb
@@ -0,0 +1,21 @@
+require 'run_loop/cli/errors'
+
+describe RunLoop::CLI::ValidationError do
+
+  it 'can be used to raise an error' do
+    expect {
+      raise RunLoop::CLI::ValidationError, 'Hey!'
+    }.to raise_error
+  end
+
+end
+
+describe RunLoop::CLI::NotImplementedError do
+
+  it 'can be used to raise an error' do
+    expect {
+      raise RunLoop::CLI::NotImplementedError, 'Hey!'
+    }.to raise_error
+  end
+
+end