Validate inside an action.

BlogPost.php

<?php namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class BlogPost extends Model
{
    public static $createRules = [
        'title' => 'required|unique:posts|max:255',
        'body' => 'required',
    ];
    
    public static $updateRules = [
        'title' => 'required|unique:posts|max:255',
        'body' => 'required',
    ];
}