Tag.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
use Illuminate\Database\Eloquent\Relations\Pivot;

/**
 * Class Tag
 * @package App\Models
 */
class Tag extends Model
{
    use HasFactory;

    /**
     * @return BelongsToMany
     */
    public function projects(): BelongsToMany {
        return $this->belongsToMany(Project::class)
            ->using(new class extends Pivot {
                use MyTrait; // ¡REEMPLAZAR POR TU TRAIT!
            });
    }
}