Please consider to use the official Laravel Tinker, it is also compatible with Lumen: laravel/tinker

An Interactive Shell to Lumen Framework.

Package Versions:

Download from packagist:

composer require vluzrmos/tinker

Add the Service Provider to the artisan file:

if(class_exists('Vluzrmos\Tinker\TinkerServiceProvider')) {
    $app->register('Vluzrmos\Tinker\TinkerServiceProvider');
}

Note: This will not affect the performance of your application.

And that is it, to see if it works do php artisan, and be sure to see the command tinker there.

To use the shell:

php artisan tinker

That package is a partial modification of illuminate/framework and that is copyright of Taylor Otwell.