AppServiceProvider.php

<?php

// app/providers/AppServiceProvider.php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider {

    // other code...
    
    public function register()
	{
	    // bind CommandTranslator interface to your implementation
        $this->app->bind(
            'Laracasts\Commander\CommandTranslator',
            'App\Commands\CommandTranslator'
        );
        
        // other code...
	}

    // other code...
}

CommandTranslator.php

<?php

// app/Commmands/CommandTranslator.php

namespace App\Commands;

use Laracasts\Commander\CommandTranslator as CommandTranslatorInterface;
use Laracasts\Commander\HandlerNotRegisteredException;

class CommandTranslator implements CommandTranslatorInterface
{
    public function toCommandHandler($command)
    {
        $commandClass = get_class($command);
        
        // this line is a little ridiculous with the substr_replace, and could probably be improved.
        $handler = 'App\\' . substr_replace($commandClass, 'Handlers\Commands\\', strpos('Commands\\', $commandClass), 13) . 'Handler';

        if (!class_exists($handler)) {
            $message = "Command handler [$handler] does not exist.";
            throw new HandlerNotRegisteredException($message);
        }

        return $handler;
    }
}