diff --git a/CHANGELOG.md b/CHANGELOG.md
index fc22c371a..df6c059f0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+### Unreleased
+
+* Typo in `\Robo\Runner:errorCondtion()` fixed as `\Robo\Runner:errorCondition()`.
+
 ### 1.2.1 12/28/2017
 
 * Fixes to tests / build only.
diff --git a/docs/extending.md b/docs/extending.md
index 55e4f17ad..adf890eac 100644
--- a/docs/extending.md
+++ b/docs/extending.md
@@ -33,6 +33,65 @@ Once you have done this, all of the tasks defined in the extension you selected
 
 Note that at the moment, it is not possible to extend Robo when using the robo.phar. This capability may be added in the future via [embedded composer](https://github.com/dflydev/dflydev-embedded-composer).
 
+## Expose discoverable command classes
+
+You can have your project expose extra Robo command files by creating them within your project's PSR-4 namespace.
+
+For example, given the following PSR-4 namespace in your `composer.json`:
+
+```json
+{
+    "autoload": {
+        "psr-4": {
+            "My\\Project\\": "./src/"
+        }
+    }
+}
+```
+
+Extra command files can be exposed by creating one or more classes under `./src/Robo/Plugin/Commands`, as shown in the
+example below:
+
+```php
+<?php
+
+namespace My\Project\Robo\Plugin\Commands;
+
+class MyCustomCommands extends \Robo\Tasks
+{
+    /**
+     * @command my-project:command-one
+     */
+    public function commandOne() { }
+
+    /**
+     * @command my-project:command-two
+     */
+    public function commandTwo() { }
+}
+```
+
+You can now access your new commands via Robo:
+
+```
+$ ./vendor/bin/robo 
+$ ./robo 
+Robo 1.2.2-dev
+
+Usage:
+  command [options] [arguments]
+...
+
+Available commands:
+  help                  Displays help for a command
+  list                  Lists commands
+ my-project
+  my-project:command-one       
+  my-project:command-two        
+```
+
+Note: remember to run `composer dump-autoload` after adding new command classes.
+ 
 ## Creating a Robo Extension
 
 A Robo tasks extension is created by advertising a Composer package of type `robo-tasks` on [Packagist](https://packagist.org/).  For an overview on how this is done, see the article [Creating your very own Composer Package](https://knpuniversity.com/screencast/question-answer-day/create-composer-package).  Specific instructions for creating Robo task extensions are provided below.
diff --git a/robo b/robo
index 2093bd119..166b9ca75 100755
--- a/robo
+++ b/robo
@@ -1,22 +1,24 @@
 #!/usr/bin/env php
 <?php
-
 /**
  * if we're running from phar load the phar autoload,
- * else let the script 'robo' search for the autoloader
+ * else let the script 'robo' search for the autoloader.
+ * If we cannot find a vendor/autoload.php file, then
+ * we will go ahead and try the phar.
  */
-if (strpos(basename(__FILE__), 'phar')) {
-    require_once 'phar://robo.phar/vendor/autoload.php';
-} else {
+$autoloaderPath = 'phar://robo.phar/vendor/autoload.php';
+if (!strpos(basename(__FILE__), 'phar')) {
     if (file_exists(__DIR__.'/vendor/autoload.php')) {
-        require_once __DIR__.'/vendor/autoload.php';
+        $autoloaderPath = __DIR__.'/vendor/autoload.php';
     } elseif (file_exists(__DIR__.'/../../autoload.php')) {
-        require_once __DIR__ . '/../../autoload.php';
-    } else {
-        require_once 'phar://robo.phar/vendor/autoload.php';
+        $autoloaderPath = __DIR__ . '/../../autoload.php';
     }
 }
+$classLoader = require $autoloaderPath;
 $runner = new \Robo\Runner();
-$runner->setSelfUpdateRepository('consolidation/robo');
+$runner
+  ->setRelativePluginNamespace('Robo\Plugin')
+  ->setSelfUpdateRepository('consolidation/robo')
+  ->setClassLoader($classLoader);
 $statusCode = $runner->execute($_SERVER['argv']);
-exit($statusCode);
+exit($statusCode);
\ No newline at end of file
diff --git a/src/ClassDiscovery/AbstractClassDiscovery.php b/src/ClassDiscovery/AbstractClassDiscovery.php
new file mode 100644
index 000000000..319543a54
--- /dev/null
+++ b/src/ClassDiscovery/AbstractClassDiscovery.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Robo\ClassDiscovery;
+
+/**
+ * Class AbstractClassDiscovery
+ *
+ * @package Robo\ClassDiscovery
+ */
+abstract class AbstractClassDiscovery implements ClassDiscoveryInterface
+{
+    /**
+     * @var string
+     */
+    protected $searchPattern = '*.php';
+
+    /**
+     * {@inheritdoc}
+     */
+    public function setSearchPattern($searchPattern)
+    {
+        $this->searchPattern = $searchPattern;
+
+        return $this;
+    }
+}
diff --git a/src/ClassDiscovery/ClassDiscoveryInterface.php b/src/ClassDiscovery/ClassDiscoveryInterface.php
new file mode 100644
index 000000000..ebbb67272
--- /dev/null
+++ b/src/ClassDiscovery/ClassDiscoveryInterface.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace Robo\ClassDiscovery;
+
+/**
+ * Interface ClassDiscoveryInterface
+ *
+ * @package Robo\Plugin\ClassDiscovery
+ */
+interface ClassDiscoveryInterface
+{
+    /**
+     * @param $searchPattern
+     *
+     * @return $this
+     */
+    public function setSearchPattern($searchPattern);
+
+    /**
+     * @return string[]
+     */
+    public function getClasses();
+
+    /**
+     * @param $class
+     *
+     * @return string|null
+     */
+    public function getFile($class);
+}
diff --git a/src/ClassDiscovery/RelativeNamespaceDiscovery.php b/src/ClassDiscovery/RelativeNamespaceDiscovery.php
new file mode 100644
index 000000000..766de3a4d
--- /dev/null
+++ b/src/ClassDiscovery/RelativeNamespaceDiscovery.php
@@ -0,0 +1,112 @@
+<?php
+
+namespace Robo\ClassDiscovery;
+
+use Symfony\Component\Finder\Finder;
+use Composer\Autoload\ClassLoader;
+
+/**
+ * Class RelativeNamespaceDiscovery
+ *
+ * @package Robo\Plugin\ClassDiscovery
+ */
+class RelativeNamespaceDiscovery extends AbstractClassDiscovery
+{
+    /**
+     * @var \Composer\Autoload\ClassLoader
+     */
+    protected $classLoader;
+
+    /**
+     * @var string
+     */
+    protected $relativeNamespace = '';
+
+    /**
+     * RelativeNamespaceDiscovery constructor.
+     *
+     * @param \Composer\Autoload\ClassLoader $classLoader
+     */
+    public function __construct(ClassLoader $classLoader)
+    {
+        $this->classLoader = $classLoader;
+    }
+
+    /**
+     * @param string $relativeNamespace
+     *
+     * @return RelativeNamespaceDiscovery
+     */
+    public function setRelativeNamespace($relativeNamespace)
+    {
+        $this->relativeNamespace = $relativeNamespace;
+
+        return $this;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function getClasses()
+    {
+        $classes = [];
+        $relativePath = $this->convertNamespaceToPath($this->relativeNamespace);
+
+        foreach ($this->classLoader->getPrefixesPsr4() as $baseNamespace => $directories) {
+            $directories = array_filter(array_map(function ($directory) use ($relativePath) {
+                return $directory.$relativePath;
+            }, $directories), 'is_dir');
+
+            if ($directories) {
+                foreach ($this->search($directories, $this->searchPattern) as $file) {
+                    $relativePathName = $file->getRelativePathname();
+                    $classes[] = $baseNamespace.$this->convertPathToNamespace($relativePath.'/'.$relativePathName);
+                }
+            }
+        }
+
+        return $classes;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getFile($class)
+    {
+        return $this->classLoader->findFile($class);
+    }
+
+    /**
+     * @param $directories
+     * @param $pattern
+     *
+     * @return \Symfony\Component\Finder\Finder
+     */
+    protected function search($directories, $pattern)
+    {
+        $finder = new Finder();
+        $finder->files()
+          ->name($pattern)
+          ->in($directories);
+
+        return $finder;
+    }
+
+    /**
+     * @param $path
+     *
+     * @return mixed
+     */
+    protected function convertPathToNamespace($path)
+    {
+        return str_replace(['/', '.php'], ['\\', ''], trim($path, '/'));
+    }
+
+    /**
+     * @return string
+     */
+    public function convertNamespaceToPath($namespace)
+    {
+        return '/'.str_replace("\\", '/', trim($namespace, '\\'));
+    }
+}
diff --git a/src/Robo.php b/src/Robo.php
index 164fdec36..161a2deed 100644
--- a/src/Robo.php
+++ b/src/Robo.php
@@ -1,6 +1,7 @@
 <?php
 namespace Robo;
 
+use Composer\Autoload\ClassLoader;
 use League\Container\Container;
 use League\Container\ContainerInterface;
 use Robo\Common\ProcessExecutor;
@@ -127,10 +128,11 @@ public static function loadConfiguration($paths, $config = null)
      * @param null|\Symfony\Component\Console\Output\OutputInterface $output
      * @param null|\Robo\Application $app
      * @param null|ConfigInterface $config
+     * @param null|\Composer\Autoload\ClassLoader $classLoader
      *
      * @return \League\Container\Container|\League\Container\ContainerInterface
      */
-    public static function createDefaultContainer($input = null, $output = null, $app = null, $config = null)
+    public static function createDefaultContainer($input = null, $output = null, $app = null, $config = null, $classLoader = null)
     {
         // Do not allow this function to be called more than once.
         if (static::hasContainer()) {
@@ -147,7 +149,7 @@ public static function createDefaultContainer($input = null, $output = null, $ap
 
         // Set up our dependency injection container.
         $container = new Container();
-        static::configureContainer($container, $app, $config, $input, $output);
+        static::configureContainer($container, $app, $config, $input, $output, $classLoader);
 
         // Set the application dispatcher
         $app->setDispatcher($container->get('eventDispatcher'));
@@ -175,8 +177,9 @@ public static function createDefaultContainer($input = null, $output = null, $ap
      * @param ConfigInterface $config
      * @param null|\Symfony\Component\Console\Input\InputInterface $input
      * @param null|\Symfony\Component\Console\Output\OutputInterface $output
+     * @param null|\Composer\Autoload\ClassLoader $classLoader
      */
-    public static function configureContainer(ContainerInterface $container, SymfonyApplication $app, ConfigInterface $config, $input = null, $output = null)
+    public static function configureContainer(ContainerInterface $container, SymfonyApplication $app, ConfigInterface $config, $input = null, $output = null, $classLoader = null)
     {
         // Self-referential container refernce for the inflector
         $container->add('container', $container);
@@ -189,6 +192,9 @@ public static function configureContainer(ContainerInterface $container, Symfony
         if (!$output) {
             $output = new \Symfony\Component\Console\Output\ConsoleOutput();
         }
+        if (!$classLoader) {
+            $classLoader = new ClassLoader();
+        }
         $config->set(Config::DECORATED, $output->isDecorated());
         $config->set(Config::INTERACTIVE, $input->isInteractive());
 
@@ -197,6 +203,7 @@ public static function configureContainer(ContainerInterface $container, Symfony
         $container->share('input', $input);
         $container->share('output', $output);
         $container->share('outputAdapter', \Robo\Common\OutputAdapter::class);
+        $container->share('classLoader', $classLoader);
 
         // Register logging and related services.
         $container->share('logStyler', \Robo\Log\RoboLogStyle::class);
@@ -245,6 +252,8 @@ function ($output, $message) use ($container) {
             );
         $container->share('commandFactory', \Consolidation\AnnotatedCommand\AnnotatedCommandFactory::class)
             ->withMethodCall('setCommandProcessor', ['commandProcessor']);
+        $container->share('relativeNamespaceDiscovery', \Robo\ClassDiscovery\RelativeNamespaceDiscovery::class)
+            ->withArgument('classLoader');
 
         // Deprecated: favor using collection builders to direct use of collections.
         $container->add('collection', \Robo\Collection\Collection::class);
diff --git a/src/Runner.php b/src/Runner.php
index 800ad281a..4e2c5c0cc 100644
--- a/src/Runner.php
+++ b/src/Runner.php
@@ -1,6 +1,7 @@
 <?php
 namespace Robo;
 
+use Composer\Autoload\ClassLoader;
 use Symfony\Component\Console\Input\ArgvInput;
 use Symfony\Component\Console\Input\StringInput;
 use Robo\Contract\BuilderAwareInterface;
@@ -43,6 +44,16 @@ class Runner implements ContainerAwareInterface
      */
     protected $selfUpdateRepository = null;
 
+    /**
+     * @var \Composer\Autoload\ClassLoader
+     */
+    protected $classLoader = null;
+
+    /**
+     * @var string
+     */
+    protected $relativePluginNamespace;
+
     /**
      * Class Constructor
      *
@@ -57,7 +68,7 @@ public function __construct($roboClass = null, $roboFile = null)
         $this->dir = getcwd();
     }
 
-    protected function errorCondtion($msg, $errorType)
+    protected function errorCondition($msg, $errorType)
     {
         $this->errorConditions[$msg] = $errorType;
     }
@@ -82,7 +93,7 @@ protected function loadRoboFile($output)
             return true;
         }
         if (!file_exists($this->dir)) {
-            $this->errorCondtion("Path `{$this->dir}` is invalid; please provide a valid absolute path to the Robofile to load.", 'red');
+            $this->errorCondition("Path `{$this->dir}` is invalid; please provide a valid absolute path to the Robofile to load.", 'red');
             return false;
         }
 
@@ -91,13 +102,13 @@ protected function loadRoboFile($output)
         $roboFilePath = $realDir . DIRECTORY_SEPARATOR . $this->roboFile;
         if (!file_exists($roboFilePath)) {
             $requestedRoboFilePath = $this->dir . DIRECTORY_SEPARATOR . $this->roboFile;
-            $this->errorCondtion("Requested RoboFile `$requestedRoboFilePath` is invalid, please provide valid absolute path to load Robofile.", 'red');
+            $this->errorCondition("Requested RoboFile `$requestedRoboFilePath` is invalid, please provide valid absolute path to load Robofile.", 'red');
             return false;
         }
         require_once $roboFilePath;
 
         if (!class_exists($this->roboClass)) {
-            $this->errorCondtion("Class {$this->roboClass} was not loaded.", 'red');
+            $this->errorCondition("Class {$this->roboClass} was not loaded.", 'red');
             return false;
         }
         return true;
@@ -120,7 +131,7 @@ public function execute($argv, $appName = null, $appVersion = null, $output = nu
             $app = Robo::createDefaultApplication($appName, $appVersion);
         }
         $commandFiles = $this->getRoboFileCommands($output);
-        return $this->run($argv, $output, $app, $commandFiles);
+        return $this->run($argv, $output, $app, $commandFiles, $this->classLoader);
     }
 
     /**
@@ -128,10 +139,11 @@ public function execute($argv, $appName = null, $appVersion = null, $output = nu
      * @param null|\Symfony\Component\Console\Output\OutputInterface $output
      * @param null|\Robo\Application $app
      * @param array[] $commandFiles
+     * @param null|ClassLoader $classLoader
      *
      * @return int
      */
-    public function run($input = null, $output = null, $app = null, $commandFiles = [])
+    public function run($input = null, $output = null, $app = null, $commandFiles = [], $classLoader = null)
     {
         // Create default input and output objects if they were not provided
         if (!$input) {
@@ -151,7 +163,7 @@ public function run($input = null, $output = null, $app = null, $commandFiles =
             $userConfig = 'robo.yml';
             $roboAppConfig = dirname(__DIR__) . '/robo.yml';
             $config = Robo::createConfiguration([$userConfig, $roboAppConfig]);
-            $container = Robo::createDefaultContainer($input, $output, $app, $config);
+            $container = Robo::createDefaultContainer($input, $output, $app, $config, $classLoader);
             $this->setContainer($container);
             // Automatically register a shutdown function and
             // an error handler when we provide the container.
@@ -164,11 +176,17 @@ public function run($input = null, $output = null, $app = null, $commandFiles =
         if ($app instanceof \Robo\Application) {
             $app->addSelfUpdateCommand($this->getSelfUpdateRepository());
             if (!isset($commandFiles)) {
-                $this->errorCondtion("Robo is not initialized here. Please run `robo init` to create a new RoboFile.", 'yellow');
+                $this->errorCondition("Robo is not initialized here. Please run `robo init` to create a new RoboFile.", 'yellow');
                 $app->addInitRoboFileCommand($this->roboFile, $this->roboClass);
                 $commandFiles = [];
             }
         }
+
+        if (!empty($this->relativePluginNamespace)) {
+            $commandClasses = $this->discoverCommandClasses($this->relativePluginNamespace);
+            $commandFiles = array_merge((array)$commandFiles, $commandClasses);
+        }
+
         $this->registerCommandClasses($app, $commandFiles);
 
         try {
@@ -212,6 +230,19 @@ public function registerCommandClasses($app, $commandClasses)
         }
     }
 
+    /**
+     * @param $relativeNamespace
+     *
+     * @return array|string[]
+     */
+    protected function discoverCommandClasses($relativeNamespace)
+    {
+        /** @var \Robo\ClassDiscovery\RelativeNamespaceDiscovery $discovery */
+        $discovery = Robo::service('relativeNamespaceDiscovery');
+        $discovery->setRelativeNamespace($relativeNamespace.'\Commands');
+        return $discovery->getClasses();
+    }
+
     /**
      * @param \Robo\Application $app
      * @param string|BuilderAwareInterface|ContainerAwareInterface $commandClass
@@ -456,10 +487,35 @@ public function getSelfUpdateRepository()
     }
 
     /**
-     * @param string $selfUpdateRepository
+     * @param $selfUpdateRepository
+     *
+     * @return $this
      */
     public function setSelfUpdateRepository($selfUpdateRepository)
     {
         $this->selfUpdateRepository = $selfUpdateRepository;
+        return $this;
+    }
+
+    /**
+     * @param \Composer\Autoload\ClassLoader $classLoader
+     *
+     * @return $this
+     */
+    public function setClassLoader(ClassLoader $classLoader)
+    {
+        $this->classLoader = $classLoader;
+        return $this;
+    }
+
+    /**
+     * @param string $relativeNamespace
+     *
+     * @return $this
+     */
+    public function setRelativePluginNamespace($relativeNamespace)
+    {
+        $this->relativePluginNamespace = $relativeNamespace;
+        return $this;
     }
 }
diff --git a/tests/plugins/Robo/Plugin/Commands/FirstCustomCommands.php b/tests/plugins/Robo/Plugin/Commands/FirstCustomCommands.php
new file mode 100644
index 000000000..b5a98452c
--- /dev/null
+++ b/tests/plugins/Robo/Plugin/Commands/FirstCustomCommands.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Robo\PluginTest\Robo\Plugin\Commands;
+
+/**
+ * Class FirstCustomCommands
+ *
+ * @package Robo\Commands
+ */
+class FirstCustomCommands
+{
+    /**
+     * @command custom:command-one
+     */
+    public function commandOne()
+    {
+    }
+
+    /**
+     * @command custom:command-two
+     */
+    public function commandTwo()
+    {
+    }
+}
diff --git a/tests/plugins/Robo/Plugin/Commands/SecondCustomCommands.php b/tests/plugins/Robo/Plugin/Commands/SecondCustomCommands.php
new file mode 100644
index 000000000..8ab310ae6
--- /dev/null
+++ b/tests/plugins/Robo/Plugin/Commands/SecondCustomCommands.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Robo\PluginTest\Robo\Plugin\Commands;
+
+/**
+ * Class FirstCustomCommands
+ *
+ * @package Robo\Commands
+ */
+class SecondCustomCommands
+{
+    /**
+     * @command custom:command-three
+     */
+    public function commandThree()
+    {
+    }
+
+    /**
+     * @command custom:command-four
+     */
+    public function commandFour()
+    {
+    }
+}
diff --git a/tests/unit/ClassDiscovery/RelativeNamespaceDiscoveryTest.php b/tests/unit/ClassDiscovery/RelativeNamespaceDiscoveryTest.php
new file mode 100644
index 000000000..bcdbf29f6
--- /dev/null
+++ b/tests/unit/ClassDiscovery/RelativeNamespaceDiscoveryTest.php
@@ -0,0 +1,92 @@
+<?php
+
+use Robo\ClassDiscovery\RelativeNamespaceDiscovery;
+use Composer\Autoload\ClassLoader;
+
+/**
+ * Class RelativeNamespaceDiscoveryTest
+ */
+class RelativeNamespaceDiscoveryTest extends \Codeception\Test\Unit
+{
+    private $ds = DIRECTORY_SEPARATOR;
+
+    public function testGetClasses()
+    {
+        $classLoader = new ClassLoader();
+        $classLoader->addPsr4('\\Robo\\PluginTest\\', [realpath(__DIR__.'/../../plugins')]);
+        $service = new RelativeNamespaceDiscovery($classLoader);
+        $service->setRelativeNamespace('Robo\Plugin');
+        $classes = $service->getClasses();
+
+        $this->assertContains('\Robo\PluginTest\Robo\Plugin\Commands\FirstCustomCommands', $classes);
+        $this->assertContains('\Robo\PluginTest\Robo\Plugin\Commands\SecondCustomCommands', $classes);
+    }
+
+    public function testGetFile()
+    {
+        $classLoader = new ClassLoader();
+        $classLoader->addPsr4('\\Robo\\PluginTest\\', [realpath(__DIR__.'/../../plugins')]);
+        $service = new RelativeNamespaceDiscovery($classLoader);
+        $service->setRelativeNamespace('Robo\Plugin');
+
+        $actual = $service->getFile('\Robo\PluginTest\Robo\Plugin\Commands\FirstCustomCommands');
+        $this->assertStringEndsWith('FirstCustomCommands.php', $actual);
+
+        $actual = $service->getFile('\Robo\PluginTest\Robo\Plugin\Commands\SecondCustomCommands');
+        $this->assertStringEndsWith('SecondCustomCommands.php', $actual);
+    }
+
+    /**
+     * @dataProvider testConvertPathToNamespaceData
+     *
+     * @param $path
+     * @param $expected
+     */
+    public function testConvertPathToNamespace($path, $expected)
+    {
+        $classLoader = new ClassLoader();
+        $discovery = new RelativeNamespaceDiscovery($classLoader);
+        $actual = $this->callProtected($discovery, 'convertPathToNamespace', [$path]);
+        $this->assertEquals($expected, $actual);
+    }
+
+    public function testConvertPathToNamespaceData()
+    {
+        return [
+          ['/A/B/C', 'A\B\C'],
+          ['A/B/C', 'A\B\C'],
+          ['A/B/C', 'A\B\C'],
+          ['A/B/C.php', 'A\B\C'],
+        ];
+    }
+
+    /**
+     * @dataProvider testConvertNamespaceToPathData
+     *
+     * @param $namespace
+     * @param $expected
+     */
+    public function testConvertNamespaceToPath($namespace, $expected)
+    {
+        $classLoader = new ClassLoader();
+        $discovery = new RelativeNamespaceDiscovery($classLoader);
+        $actual = $this->callProtected($discovery, 'convertNamespaceToPath', [$namespace]);
+        $this->assertEquals($expected, $actual);
+    }
+
+    public function testConvertNamespaceToPathData()
+    {
+        return [
+          ['A\B\C', '/A/B/C'],
+          ['\A\B\C\\', '/A/B/C'],
+          ['A\B\C\\', '/A/B/C'],
+        ];
+    }
+
+    protected function callProtected($object, $method, $args = [])
+    {
+        $r = new \ReflectionMethod($object, $method);
+        $r->setAccessible(true);
+        return $r->invokeArgs($object, $args);
+    }
+}