AppServiceProvider.php

<?php

namespace SnPortal\Providers;

use SnPortal\Models\Client;
use SnPortal\Observers\ClientObserver;
use Illuminate\Support\ServiceProvider;


class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Client::observe(ClientObserver::class);
    }

    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }
}

ClientObserver.php

<?php
namespace SnPortal\Observers;

use SnPortal\Models\Client;

class ClientObserver
{
    /**
     * Listen to the Client creating event.
     *
     * @param  Client $client
     * @return void
     */
    public function creating(Client $client)
    {
        $client->created_by = (App::runningInConsole()?1:\Auth::user()->id); // Se estiver rodando via artisan, atribui 1
        $client->updated_by = (App::runningInConsole()?1:\Auth::user()->id); // Se estiver rodando via artisan, atribui 1
    }

    /**
     * Listen to the Client updating event.
     *
     * @param  Client  $client
     * @return void
     */
    public function updating(Client $client)
    {
        $client->updated_by = (App::runningInConsole()?1:\Auth::user()->id); // Se estiver rodando via artisan, atribui 1
    }
}