@mentions

Comment bodies are scanned for @handle tokens on write and edit. Handles are always stored as CommentMention rows; set a resolver to link them to models and fire CommentMentioned. The resolver is a class, not a closure — php artisan config:cache cannot store a closure:

// app/Mentions/ResolveMention.php
namespace App\Mentions;

use App\Models\User;

final class ResolveMention
{
    public function __invoke(string $handle): ?User
    {
        return User::where('username', $handle)->first();
    }
}

// config/comments.php — an invokable class, or [ResolveMention::class, 'someMethod']
'mention_resolver' => \App\Mentions\ResolveMention::class,

$comment = Comments::on($post)->body('thanks @alice!')->post();
$comment->mentions; // CommentMention rows (handle + optional mentionable)

• A handle is @ followed by letters, digits, _, . or - (@john.doe), but it ends on a letter, digit or underscore — so “thanks @alice.” mentions alice. It must not follow a word character, so an email address like [email protected] is not a mention.
• The resolver receives the handle without the @ and returns an Eloquent model or null. It is built through the container, so it may take constructor dependencies.

When CommentMentioned fires

• Only for an approved comment, once per person. A comment the moderation layer holds back — require_approval, a blocklist pending or hidden match, a moderator’s hide — notifies nobody until Comments::approve(); then each resolved mention fires once.
• Each handle is stored once per comment. An edit fires it only for people the comment has not notified yet — handles still in the body keep their rows, removed ones are deleted, and re-mentioning the same person, even under another handle, is not a new mention.
• A hide-and-approve round trip never notifies anyone twice.

A [class, method] resolver

Instead of an invokable class, point the resolver at a [Class::class, 'method'] pair. The class is built through the container too, so the pair stays config:cache-safe:

// config/comments.php
'mention_resolver' => [App\Support\MentionResolver::class, 'resolve'],

// app/Support/MentionResolver.php — built through the container
namespace App\Support;

use App\Models\User;

final class MentionResolver
{
    public function resolve(string $handle): ?User
    {
        return User::where('username', $handle)->first();
    }
}

Notifying mentioned users

use Illuminate\Support\Facades\Event;
use RoundlyConsulting\Comments\Events\CommentMentioned;

Event::listen(function (CommentMentioned $event): void {
    $event->mention->handle;       // 'alice'
    $event->mention->mentionable;  // the resolved model (e.g. your User)
    $event->mention->comment;      // the Comment that mentions them
});