diff --git a/lib/Command/AddBotParticipant.php b/lib/Command/AddBotParticipant.php
new file mode 100644
index 0000000..f482782
--- /dev/null
+++ b/lib/Command/AddBotParticipant.php
@@ -0,0 +1,123 @@
+<?php
+
+namespace OCA\NCdiscordhook\Command;
+
+use OCA\Talk\Manager as TalkManager;
+use OCA\Talk\Participant;
+use OCA\Talk\Model\Attendee;
+use OCA\Talk\Model\AttendeeMapper;
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\DB\Exception;
+use OCP\IConfig;
+use OCP\IDBConnection;
+use OCP\IUserManager;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class AddBotParticipant extends Command {
+    public static defaultName = 'ncdiscordhook:add-bot-participant';
+    public static defaultDescription = 'Add talk-bot as a participant in all configured rooms (fixes Chat API 404)';
+
+    private IConfig $config;
+    private IDBConnection $db;
+    private TalkManager $talkManager;
+    private IUserManager $userManager;
+    private AttendeeMapper $attendeeMapper;
+
+    private const APP_ID = 'ncdiscordhook';
+
+    public function __construct(
+        IConfig $config,
+        IDBConnection $db,
+        TalkManager $talkManager,
+        IUserManager $userManager,
+        AttendeeMapper $attendeeMapper,
+    ) {
+        parent::__construct();
+        $this->config = $config;
+        $this->db = $db;
+        $this->talkManager = $talkManager;
+        $this->userManager = $userManager;
+        $this->attendeeMapper = $attendeeMapper;
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output): int {
+        $output->writeln('Reading configured rooms from app config...');
+
+        // Get configured rooms from app config (stored as JSON)
+        $roomsJson = $this->config->getAppValue(self::APP_ID, 'rooms', '[]');
+        $rooms = @json_decode($roomsJson, true);
+        if (!is_array($rooms)) {
+            $output->writeln('<error>No configured rooms found.</error>');
+            return 1;
+        }
+
+        $roomTokens = array_keys($rooms);
+        $output->writeln('Found ' . count($roomTokens) . ' configured room(s).');
+
+        // Get talk-bot user
+        $botUser = $this->userManager->get('talk-bot');
+        if ($botUser === null) {
+            $output->writeln('<error>talk-bot user not found. Creating it...</error>');
+            // talk-bot might not exist yet
+            $output->writeln('<comment>Run: php occ user:add --password-from-env talk-bot</comment>');
+            return 1;
+        }
+
+        // Get table prefix
+        $sysPrefix = $this->config->getSystemValueString('dbtableprefix', '');
+        $talkPrefix = $this->config->getAppValue('spreed', 'databaseprefix', $sysPrefix);
+        $attendeeTable = $talkPrefix . 'talk_attendee';
+
+        $added = 0;
+        $skipped = 0;
+
+        foreach ($roomTokens as $token) {
+            try {
+                $room = $this->talkManager->getRoomForToken($token);
+                $roomId = $room->getId();
+
+                // Check if talk-bot is already an attendee
+                try {
+                    $attendee = $this->attendeeMapper->findByActor($roomId, 'users', 'talk-bot');
+                    $output->writeln('  <info>Room ' . $token . ': talk-bot already an attendee (id=' . $roomId . ')</info>');
+                    $skipped++;
+                    continue;
+                } catch (DoesNotExistException $e) {
+                    // Not found - will create
+                } catch (\Exception $e) {
+                    $output->writeln('  <warning>Room ' . $token . ': query error - ' . $e->getMessage() . '</warning>');
+                    $skipped++;
+                    continue;
+                }
+
+                // Create attendee record
+                $newAttendee = new Attendee();
+                $newAttendee->setRoomId($roomId);
+                $newAttendee->setActorType('users');
+                $newAttendee->setActorId('talk-bot');
+                $newAttendee->setDisplayName('talk-bot');
+                $newAttendee->setParticipantType(Participant::PERMISSIONS_DEFAULT);
+                $newAttendee->setPermissions(Participant::PERMISSIONS_MAX_DEFAULT);
+                $newAttendee->setNotificationLevel(3); // Full level
+                $newAttendee->setFavorite(false);
+                $newAttendee->setArchived(false);
+
+                try {
+                    $this->attendeeMapper->insert($newAttendee);
+                    $output->writeln('  <info>Room ' . $token . ': added talk-bot as attendee (room_id=' . $roomId . ')</info>');
+                    $added++;
+                } catch (Exception $e) {
+                    $output->writeln('  <warning>Room ' . $token . ': insert failed - ' . $e->getMessage() . '</warning>');
+                }
+            } catch (\Exception $e) {
+                $output->writeln('  <error>Room ' . $token . ': ' . $e->getMessage() . '</error>');
+            }
+        }
+
+        $output->writeln('');
+        $output->writeln('<info>Done: ' . $added . ' added, ' . $skipped . ' skipped.</info>');
+        return 0;
+    }
+}
diff --git a/lib/Controller/WebhookController.php b/lib/Controller/WebhookController.php
index b9a07b2..da09967 100644
--- a/lib/Controller/WebhookController.php
+++ b/lib/Controller/WebhookController.php
@@ -13,9 +13,11 @@ use OCP\AppFramework\Http\Attribute\AdminRequired;
 use OCP\App\IAppManager;
 use OCP\IAppConfig;
 use OCP\IConfig;
+use OCP\Http\Client\IClientService;
 use OCP\IGroupManager;
 use OCP\IRequest;
 use OCP\IUserSession;
+use OCA\Talk\ParticipantService;
 use Psr\Log\LoggerInterface;
 
 class WebhookController extends Controller {
@@ -26,8 +28,9 @@ class WebhookController extends Controller {
     private IGroupManager $groupManager;
     private IConfig $config;
     private IAppConfig $appConfig;
+    private IClientService $clientService;
 
-    public function __construct(IRequest $request, TalkService $talkService, LoggerInterface $logger, IAppManager $appManager, IUserSession $userSession, IGroupManager $groupManager, IConfig $config, IAppConfig $appConfig) {
+    public function __construct(IRequest $request, TalkService $talkService, LoggerInterface $logger, IAppManager $appManager, IUserSession $userSession, IGroupManager $groupManager, IConfig $config, IAppConfig $appConfig, IClientService $clientService) {
         parent::__construct('ncdiscordhook', $request);
         $this->talkService = $talkService;
         $this->logger = $logger;
@@ -36,6 +39,7 @@ class WebhookController extends Controller {
         $this->groupManager = $groupManager;
         $this->config = $config;
         $this->appConfig = $appConfig;
+        $this->clientService = $clientService;
     }
 
     /**
@@ -201,6 +205,9 @@ class WebhookController extends Controller {
      * Debug endpoint to verify the app is working.
      *
      * URL: GET /apps/ncdiscordhook/debug
+     * Query params:
+     *   - webhook_url: Full webhook URL to diagnose (e.g. /apps/ncdiscordhook/bot-webhook/{room}/{token})
+     *   - test_post=1: Actually POST a test message to the room
      */
     #[PublicPage]
     #[NoCSRFRequired]
@@ -323,9 +330,338 @@ class WebhookController extends Controller {
             $info['talk_debug_error_trace'] = substr($e->getTraceAsString(), 0, 2000);
         }
 
+        // ── Webhook URL debug ─────────────────────────────────────────
+        // Parse webhook URL if provided via query param
+        $webhookUrl = $this->request->getParam('webhook_url', '');
+        $doTestPost = (bool) $this->request->getParam('test_post', 0);
+        if ($webhookUrl !== '') {
+            $info['webhook_debug'] = $this->debugWebhookUrl($webhookUrl);
+            if ($doTestPost) {
+                $info['test_post'] = $this->runTestPost($webhookUrl);
+            }
+        }
+
         return new DataResponse($info);
     }
 
+    /**
+     * Debug a webhook URL step by step.
+     */
+    private function debugWebhookUrl(string $webhookUrl): array {
+        $result = [];
+
+        // 1. Parse the URL
+        $parsed = parse_url($webhookUrl);
+        $result['parsed_url'] = $parsed;
+
+        $path = $parsed['path'] ?? '';
+        $segments = explode('/', trim($path, '/'));
+
+        // Expected: apps/ncdiscordhook/bot-webhook/{roomToken}/{token}
+        if (count($segments) >= 5 && $segments[0] === 'apps' && $segments[1] === 'ncdiscordhook' && $segments[2] === 'bot-webhook') {
+            $roomToken = $segments[3];
+            $token = $segments[4];
+            $result['room_token'] = $roomToken;
+            $result['token'] = $token;
+            $result['url_valid'] = true;
+
+            // 2. Validate auth token
+            $valid = $this->talkService->validateAuthToken($roomToken, $token);
+            $result['auth_token_valid'] = $valid;
+
+            // 3. Check if room is configured
+            $configured = $this->talkService->isBotEnabledForRoom($roomToken);
+            $result['room_configured'] = $configured;
+
+            // 4. Check bot user
+            try {
+                $bot = $this->talkService->getBotUser();
+                $result['bot_user_exists'] = $bot !== null;
+                $result['bot_uid'] = $bot !== null ? $bot->getUID() : null;
+            } catch (\Exception $e) {
+                $result['bot_user_error'] = $e->getMessage();
+            }
+
+            // 5. Check bot password
+            $result['has_bot_password'] = $this->talkService->hasBotPassword();
+            try {
+                $pw = $this->talkService->getBotPassword();
+                $result['bot_password_length'] = $pw !== null ? strlen($pw) : null;
+                $result['bot_password_starts_with'] = $pw !== null ? substr($pw, 0, 4) . '...' : null;
+            } catch (\Exception $e) {
+                $result['bot_password_error'] = $e->getMessage();
+            }
+
+            // 6. Check base URL
+            $baseUrl = $this->talkService->getBaseUrl();
+            $result['base_url'] = $baseUrl;
+            $result['base_url_scheme'] = parse_url($baseUrl, PHP_URL_SCHEME) ?? null;
+            $result['base_url_host'] = parse_url($baseUrl, PHP_URL_HOST) ?? null;
+
+            // 7. Check if room exists in DB
+            try {
+                $sysPrefix = $this->config->getSystemValueString('dbtableprefix', '');
+                $talkPrefix = $this->config->getAppValue('spreed', 'databaseprefix', $sysPrefix);
+                $roomTable = $this->talkService->detectTalkTableFromCatalog('talk_rooms', 'spreed_room');
+                $result['room_table'] = $roomTable;
+
+                if ($roomTable !== null) {
+                    $stmt = $this->talkService->getDbConnection()->executeQuery(
+                        'SELECT token, type, name, object_type, object_id
+                         FROM "' . $roomTable . '" WHERE token = ?',
+                        [$roomToken],
+                    );
+                    $row = $stmt->fetch();
+                    $stmt->closeCursor();
+
+                    $result['room_found_in_db'] = $row !== false;
+                    if ($row !== false) {
+                        $result['room_type'] = (int)$row['type'];
+                        // readable_name may not exist in all Talk versions
+                        $result['room_readable_name'] = isset($row['readable_name']) ? ($row['readable_name'] ?: null) : null;
+                        $result['room_name'] = $row['name'] ?: null;
+                        $result['room_object_type'] = $row['object_type'] ?: null;
+                        $result['room_object_id'] = $row['object_id'] ?: null;
+
+                        // 8. Check room name doesn't look like a DM JSON
+                        if (is_string($row['name']) && str_starts_with($row['name'], '["')) {
+                            $result['room_name_is_json_dm'] = true;
+                            $result['room_name_is_json_dm_warning'] = 'Room name looks like a DM JSON array — this room type is normally filtered out but is explicitly configured.';
+                        }
+                    }
+                }
+            } catch (\Exception $e) {
+                $result['db_check_error'] = $e->getMessage();
+            }
+
+            // 9. Construct Chat API endpoint
+            $chatEndpoint = $baseUrl . '/ocs/v2.php/apps/spreed/api/v1/chat/' . $roomToken;
+            $result['chat_api_endpoint'] = $chatEndpoint;
+
+            // 10. Construct Basic auth header (without exposing full password)
+            try {
+                $pw = $this->talkService->getBotPassword();
+                if ($pw !== null) {
+                    $b64 = base64_encode('talk-bot:' . $pw);
+                    $result['basic_auth_header_prefix'] = 'Basic ' . substr($b64, 0, 20) . '...';
+                    $result['basic_auth_header_length'] = strlen($b64);
+                }
+            } catch (\Exception $e) {
+                $result['basic_auth_error'] = $e->getMessage();
+            }
+
+            // 11. Test HTTP connectivity to the Chat API endpoint
+            try {
+                $client = $this->clientService->newClient();
+                $response = $client->get($chatEndpoint, [
+                    'headers' => [
+                        'OCS-Expect-Formatted' => 'json',
+                        'Authorization' => 'Basic ' . base64_encode('talk-bot:' . ($this->talkService->getBotPassword() ?? 'ERROR')),
+                    ],
+                    'nextcloud' => [
+                        'allow_local_address' => true,
+                    ],
+                ]);
+                $result['http_test_status'] = $response->getStatusCode();
+                $result['http_test_body'] = $response->getBody();
+            } catch (\Guzzle\Exception\ConnectException $e) {
+                $result['http_test_error'] = 'Connection failed: ' . $e->getMessage();
+                $result['http_test_error_type'] = 'connection';
+            } catch (\Guzzle\Exception\ServerException $e) {
+                $result['http_test_status'] = $e->getResponse() ? $e->getResponse()->getStatusCode() : null;
+                $result['http_test_body'] = $e->getResponse() ? $e->getResponse()->getBody() : null;
+                $result['http_test_error'] = 'Server error: ' . $e->getMessage();
+                $result['http_test_error_type'] = 'server';
+            } catch (\Guzzle\Exception\ClientException $e) {
+                $result['http_test_status'] = $e->getResponse() ? $e->getResponse()->getStatusCode() : null;
+                $result['http_test_body'] = $e->getResponse() ? $e->getResponse()->getBody() : null;
+                $result['http_test_error'] = 'Client error: ' . $e->getMessage();
+                $result['http_test_error_type'] = 'client';
+            } catch (\Exception $e) {
+                $result['http_test_error'] = $e->getMessage();
+                $result['http_test_error_type'] = 'other';
+            }
+
+            // 12. Summary of issues
+            $issues = [];
+            if (!$result['auth_token_valid'] ?? false === false) {
+                $issues[] = 'Auth token is INVALID for this room';
+            }
+            if (!($result['room_configured'] ?? false)) {
+                $issues[] = 'Room is NOT configured (bot not enabled)';
+            }
+            if (!($result['bot_user_exists'] ?? false)) {
+                $issues[] = 'talk-bot user does NOT exist';
+            }
+            if (!($result['has_bot_password'] ?? false)) {
+                $issues[] = 'Bot password is NOT configured';
+            }
+            if (($result['room_found_in_db'] ?? false) === false) {
+                $issues[] = 'Room NOT found in Talk database';
+            }
+            if (($result['http_test_status'] ?? null) !== null && ($result['http_test_status'] ?? 0) >= 400) {
+                $issues[] = 'Chat API returned HTTP ' . ($result['http_test_status'] ?? 'unknown');
+            }
+            if (isset($result['http_test_error'])) {
+                $issues[] = 'HTTP test failed: ' . $result['http_test_error'];
+            }
+            $result['issues'] = $issues;
+            $result['summary'] = empty($issues) ? 'All checks passed — if webhook still fails, check Talk server logs' : implode('; ', $issues);
+
+        } else {
+            $result['url_valid'] = false;
+            $result['parse_error'] = 'URL does not match expected pattern: /apps/ncdiscordhook/bot-webhook/{roomToken}/{token}';
+        }
+
+        return $result;
+    }
+
+    /**
+     * Run a test post to simulate a full webhook delivery.
+     */
+    private function runTestPost(string $webhookUrl): array {
+        $result = [];
+
+        // Parse URL to get roomToken and token
+        $parsed = parse_url($webhookUrl);
+        $path = $parsed['path'] ?? '';
+        $segments = explode('/', trim($path, '/'));
+
+        if (!(count($segments) >= 5 && $segments[0] === 'apps' && $segments[1] === 'ncdiscordhook' && $segments[2] === 'bot-webhook')) {
+            return ['error' => 'Invalid webhook URL format'];
+        }
+
+        $roomToken = $segments[3];
+        $token = $segments[4];
+        $result['room_token'] = $roomToken;
+        $result['token'] = $token;
+
+        // Step 1: Validate auth token
+        $authValid = $this->talkService->validateAuthToken($roomToken, $token);
+        $result['step_1_auth_token'] = $authValid ? 'OK' : 'FAIL — token not found for this room';
+        if (!$authValid) {
+            $result['steps'] = $result;
+            return $result;
+        }
+
+        // Step 2: Build a realistic Discord-style test payload
+        $testPayload = [
+            'content' => '🔧 **Test message from ncdiscordhook debug**\n\nThis is a test message sent via the debug endpoint. If you see this, the webhook pipeline is working!',
+            'embeds' => [
+                [
+                    'title' => 'Webhook Test',
+                    'description' => 'Sent at ' . date('Y-m-d H:i:s T'),
+                    'color' => 3066993,
+                    'footer' => [
+                        'text' => 'ncdiscordhook debug endpoint',
+                    ],
+                ],
+            ],
+            'username' => 'Debug Test',
+            'avatar_url' => null,
+        ];
+
+        // Step 3: Map payload to message
+        $message = $this->talkService->mapPayload($testPayload);
+        $result['step_2_map_payload'] = $message !== '' ? 'OK — "' . substr($message, 0, 100) . '..." (' . strlen($message) . ' chars)' : 'FAIL — empty message';
+        if ($message === '') {
+            return $result;
+        }
+
+        // Step 4: Get sender name
+        $senderName = $this->talkService->getSenderName($testPayload);
+        $result['step_3_sender_name'] = $senderName;
+
+        // Step 5: Check bot password
+        $botPassword = $this->talkService->getBotPassword();
+        $result['step_4_bot_password'] = $botPassword !== null ? 'OK (' . strlen($botPassword) . ' chars)' : 'FAIL — not configured';
+        if ($botPassword === null) {
+            return $result;
+        }
+
+        // Step 6: Check bot enabled for room
+        $botEnabled = $this->talkService->isBotEnabledForRoom($roomToken);
+        $result['step_5_bot_enabled'] = $botEnabled ? 'OK' : 'FAIL — room not enabled in config';
+        if (!$botEnabled) {
+            return $result;
+        }
+
+        // Step 7: Get base URL
+        $baseUrl = $this->talkService->getBaseUrl();
+        $result['step_6_base_url'] = $baseUrl !== '' ? $baseUrl : 'FAIL — not configured';
+        if ($baseUrl === '') {
+            return $result;
+        }
+
+        // Step 8: Build the Chat API request (OCS path with CSRF bypass)
+        $endpoint = $baseUrl . '/ocs/v2.php/apps/spreed/api/v1/chat/' . $roomToken;
+        $result['step_7_endpoint'] = $endpoint;
+
+        // Step 9: Try the actual Chat API POST
+        try {
+            $client = $this->clientService->newClient();
+            $response = $client->post($endpoint, [
+                'body' => json_encode([
+                    'message' => $message,
+                    'actorType' => 'users',
+                    'actorId' => 'talk-bot',
+                    'actorDisplayName' => $senderName,
+                ]),
+                'headers' => [
+                    'OCS-Expect-Formatted' => 'json',
+                    'OCS-APIRequest' => '1',
+                    'Authorization' => 'Basic ' . base64_encode('talk-bot:' . $botPassword),
+                    'Content-Type' => 'application/json',
+                ],
+                'nextcloud' => [
+                    'allow_local_address' => true,
+                ],
+            ]);
+
+            $statusCode = $response->getStatusCode();
+            $body = $response->getBody();
+            $result['step_8_http_status'] = $statusCode;
+            $result['step_8_http_body'] = $body;
+
+            if ($statusCode === 200) {
+                $result['step_8_result'] = 'SUCCESS — message posted to Talk!';
+                $result['overall'] = 'Webhook pipeline is WORKING. If messages still fail from Discord, check your Discord webhook configuration.';
+            } else {
+                $result['step_8_result'] = 'FAIL — HTTP ' . $statusCode;
+
+                // Parse OCS error if possible
+                if (strpos($body, 'ocs') !== false) {
+                    $parsedBody = @json_decode($body, true);
+                    if (is_array($parsedBody) && isset($parsedBody['ocs']['meta']['message'])) {
+                        $result['step_8_error_message'] = $parsedBody['ocs']['meta']['message'];
+                    }
+                }
+            }
+        } catch (\Guzzle\Exception\ConnectException $e) {
+            $result['step_8_result'] = 'FAIL — Connection error';
+            $result['step_8_error'] = $e->getMessage();
+        } catch (\Guzzle\Exception\ServerException $e) {
+            $result['step_8_result'] = 'FAIL — Server error (5xx)';
+            $result['step_8_error'] = $e->getMessage();
+            if ($e->getResponse()) {
+                $result['step_8_status'] = $e->getResponse()->getStatusCode();
+                $result['step_8_body'] = $e->getResponse()->getBody();
+            }
+        } catch (\Guzzle\Exception\ClientException $e) {
+            $result['step_8_result'] = 'FAIL — Client error (4xx)';
+            $result['step_8_error'] = $e->getMessage();
+            if ($e->getResponse()) {
+                $result['step_8_status'] = $e->getResponse()->getStatusCode();
+                $result['step_8_body'] = $e->getResponse()->getBody();
+            }
+        } catch (\Exception $e) {
+            $result['step_8_result'] = 'FAIL — Unexpected error';
+            $result['step_8_error'] = $e->getMessage();
+        }
+
+        return $result;
+    }
+
     /**
      * Get available Talk rooms.
      *
diff --git a/lib/Service/TalkService.php b/lib/Service/TalkService.php
index 714868e..8421b7e 100644
--- a/lib/Service/TalkService.php
+++ b/lib/Service/TalkService.php
@@ -116,16 +116,41 @@ class TalkService {
             return rtrim($overwritten, '/');
         }
 
-        // Use the first trusted domain as the base URL.
-        // This is the only reliable method when the HTTP client blocks localhost
-        // and overwrite.cli.url points to an internal Docker address.
+        // Prefer a public (non-loopback, non-private) trusted domain.
+        // In Docker/container deployments, trusted_domains[0] is often 127.0.0.1
+        // which is unreachable from within the container.
         $trusted = $this->config->getSystemValue('trusted_domains', []);
+        foreach ($trusted as $domain) {
+            if ($domain === '') {
+                continue;
+            }
+            // Already has a scheme — trust it as-is
+            if (preg_match('#^https?://#', $domain)) {
+                return rtrim($domain, '/');
+            }
+            // Skip loopback and localhost
+            $lower = strtolower($domain);
+            if ($lower === 'localhost'
+                || $lower === '127.0.0.1'
+                || $lower === '::1'
+            ) {
+                continue;
+            }
+            // Skip private IP ranges (10.x, 172.16-31.x, 192.168.x)
+            if (preg_match(
+                '/^(10\.\d{1,3}|172\.(1[6-9]|2\d|3[01])|192\.168)\./i',
+                $domain
+            )) {
+                continue;
+            }
+            return 'https://' . $domain;
+        }
+
+        // Fallback to first trusted domain (may be localhost; caller may fail)
         if (!empty($trusted[0])) {
-            // Check if trusted_domains[0] already has a scheme
             if (preg_match('#^https?://#', $trusted[0])) {
                 return rtrim($trusted[0], '/');
             }
-            // Use https by default for trusted domains
             return 'https://' . $trusted[0];
         }
 
@@ -706,6 +731,7 @@ class TalkService {
                 'body' => $jsonBody,
                 'headers' => [
                     'OCS-Expect-Formatted' => 'json',
+                    'OCS-APIRequest' => '1',
                     'Authorization' => 'Basic ' . $credentials,
                     'Content-Type' => 'application/json',
                 ],
@@ -715,7 +741,7 @@ class TalkService {
             ]);
 
             $statusCode = $response->getStatusCode();
-            if ($statusCode === Http::STATUS_OK) {
+            if ($statusCode >= 200 && $statusCode < 300) {
                 $this->logger->info('NCdiscordhook: message posted to room ' . $roomToken, [
                     'app' => self::APP_ID,
                 ]);
@@ -838,5 +864,68 @@ class TalkService {
         if (isset($config['sender_name'])) {
             $this->setSenderName($config['sender_name']);
         }
+
+        // Ensure talk-bot is a participant in all configured rooms
+        $this->ensureBotParticipants();
+    }
+
+    /**
+     * Add talk-bot user as a participant in all configured rooms.
+     * Required so the Chat API accepts requests authenticated as talk-bot.
+     */
+    private function ensureBotParticipants(): void {
+        if ($this->talkParticipantService === null) {
+            $this->logger->info('NCdiscordhook: ParticipantService not available, skipping auto-join for talk-bot', ['app' => self::APP_ID]);
+            return;
+        }
+
+        $rooms = $this->getRooms();
+        if (empty($rooms)) {
+            return;
+        }
+
+        // Get the talk-bot user
+        $botUser = $this->userManager->get('talk-bot');
+        if ($botUser === null) {
+            $this->logger->warning('NCdiscordhook: talk-bot user not found', ['app' => self::APP_ID]);
+            return;
+        }
+
+        foreach (array_keys($rooms) as $token) {
+            try {
+                $room = $this->talkManager->getRoomForToken($token);
+                // Check if talk-bot is already a participant
+                $participants = $room->getParticipants();
+                $actors = [];
+                if (is_array($participants)) {
+                    $actors = $participants['actors'] ?? [];
+                } elseif (is_object($participants) && method_exists($participants, 'getActors')) {
+                    $actors = $participants->getActors();
+                }
+                $hasBot = false;
+                foreach ($actors as $actor) {
+                    if (isset($actor['type']) && $actor['type'] === 'users' && isset($actor['actorId']) && $actor['actorId'] === 'talk-bot') {
+                        $hasBot = true;
+                        break;
+                    }
+                }
+                if (!$hasBot) {
+                    $this->talkParticipantService->addParticipant(
+                        $room,
+                        $botUser,
+                        \OCA\Talk\Participant::TYPE_USER,
+                        \OCA\Talk\Participant::PERMISSIONS_DEFAULT,
+                    );
+                    $this->logger->info('NCdiscordhook: added talk-bot as participant in room ' . $token, [
+                        'app' => self::APP_ID,
+                    ]);
+                }
+            } catch (\Exception $e) {
+                $this->logger->warning('NCdiscordhook: failed to add talk-bot to room ' . $token, [
+                    'app' => self::APP_ID,
+                    'error' => $e->getMessage(),
+                ]);
+            }
+        }
     }
 }