Add AI hint that the message might contain ai generated text

lib/Db/LocalMessage.php

@@ -53,6 +53,8 @@
  * @method setRaw(string|null $raw)
  * @method bool getRequestMdn()
  * @method setRequestMdn(bool $mdn)
+ * @method void setAiGenerated(bool $aiGenerated)
+ * @method bool|null getAiGenerated()
  */
 class LocalMessage extends Entity implements JsonSerializable {
 	public const TYPE_OUTGOING = 0;
@@ -141,6 +143,8 @@ class LocalMessage extends Entity implements JsonSerializable {
 	/** @var bool */
 	protected $requestMdn;
 
+	protected $aiGenerated = false;
+
 	public function __construct() {
 		$this->addType('type', 'integer');
 		$this->addType('accountId', 'integer');
@@ -155,6 +159,7 @@ public function __construct() {
 		$this->addType('smimeEncrypt', 'boolean');
 		$this->addType('status', 'integer');
 		$this->addType('requestMdn', 'boolean');
+		$this->addType('aiGenerated', 'boolean');
 
 	}
 
@@ -227,4 +232,7 @@ public function setRecipients(array $recipients): void {
 	public function getRecipients(): ?array {
 		return $this->recipients;
 	}
+	public function isAiGenerated(): bool {
+		return $this->getAiGenerated() === true;
+	}
 }

lib/Db/Message.php

@@ -28,6 +28,8 @@
  * @method string|null getInReplyTo()
  * @method string|null getThreadRootId()
  * @method void setMailboxId(int $mailbox)
+ * @method void setFlagAiGenerated(bool $aiGenerated)
+ * @method bool|null getFlagAiGenerated()
  * @method int getMailboxId()
  * @method void setSubject(string $subject)
  * @method string getSubject()
@@ -91,6 +93,7 @@
 	];
 
 	protected $uid;
+	protected $flagAiGenerated;
 	protected $messageId;
 	protected $references;
 	protected $inReplyTo;
@@ -167,6 +170,7 @@
 		$this->addType('flagAttachments', 'boolean');
 		$this->addType('flagImportant', 'boolean');
 		$this->addType('flagMdnsent', 'boolean');
+		$this->addType('flagAiGenerated', 'boolean');
 		$this->addType('updatedAt', 'integer');
 		$this->addType('imipMessage', 'boolean');
 		$this->addType('imipProcessed', 'boolean');
@@ -345,6 +349,7 @@
 			'subject' => $this->getSubject(),
 			'dateInt' => $this->getSentAt(),
 			'flags' => [
+				'aiGenerated' => ($this->getFlagAiGenerated() === true),
 				'seen' => ($this->getFlagSeen() === true),
 				'flagged' => ($this->getFlagFlagged() === true),
 				'answered' => ($this->getFlagAnswered() === true),
@@ -356,6 +361,7 @@
 				'$junk' => ($this->getFlagJunk() === true),
 				'$notjunk' => ($this->getFlagNotjunk() === true),
 				'$mdnsent' => ($this->getFlagMdnsent() === true),
+				'aiGenerated' => ($this->getFlagAiGenerated() === true),
 			],
 			'tags' => $indexed,
 			'from' => $this->getFrom()->jsonSerialize(),

lib/IMAP/ImapMessageFetcher.php

@@ -64,6 +64,8 @@
 	private string $rawReferences = '';
 	private string $dispositionNotificationTo = '';
 	private bool $hasDkimSignature = false;
+
+	private bool $isAiGenerated = false;
 	private array $phishingDetails = [];
 	private ?string $unsubscribeUrl = null;
 	private bool $isOneClickUnsubscribe = false;
@@ -259,7 +261,7 @@
 		$messageId = new Horde_Mail_Rfc822_Identification($envelope->message_id);
 		$inReplyTo = new Horde_Mail_Rfc822_Identification($envelope->in_reply_to);
 
 		return new IMAPMessage(
 			$this->uid,
 			$messageId->ids[0] ?? '',
 			$fetch->getFlags(),
@@ -290,6 +292,7 @@
 			$signatureIsValid,
 			$this->htmlService, // TODO: drop the html service dependency
 			$this->isPgpMimeEncrypted,
+			$this->isAiGenerated,
 		);
 	}
 
@@ -554,6 +557,10 @@
 		$dkimSignatureHeader = $parsedHeaders->getHeader('dkim-signature');
 		$this->hasDkimSignature = $dkimSignatureHeader !== null;
 
+		$aiGeneratedHeader = $parsedHeaders->getHeader('x-ai-generated');
+		$this->isAiGenerated = $aiGeneratedHeader !== null
+			&& strtolower($aiGeneratedHeader->value_single) === 'true';
+
 		if ($this->runPhishingCheck) {
 			$this->phishingDetails = $this->phishingDetectionService->checkHeadersForPhishing($this->userId, $parsedHeaders, $fetch->getFlags(), $this->hasHtmlMessage, $this->htmlMessage);
 		}

lib/Migration/Version5090Date20260528000000.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\Mail\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version5090Date20260528000000 extends SimpleMigrationStep {
+
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+		$table = $schema->getTable('mail_messages');
+
+		if (!$table->hasColumn('flag_ai_generated')) {
+			$table->addColumn('flag_ai_generated', Types::BOOLEAN, [
+				'notnull' => false,
+				'default' => false,
+			]);
+		}
+
+		return $schema;
+	}
+}
+

lib/Model/IMAPMessage.php

@@ -81,6 +81,7 @@ class IMAPMessage implements IMessage, JsonSerializable {
 	private bool $isSigned;
 	private bool $signatureIsValid;
 	private bool $isPgpMimeEncrypted;
+	private bool $isAiGenerated = false;
 
 	/**
 	 * @param list<IMAPAttachment> $inlineAttachments
@@ -151,6 +152,10 @@ public static function generateMessageId(): string {
 		return Horde_Mime_Headers_MessageId::create('nextcloud-mail-generated')->value;
 	}
 
+	public function isAiGenerated(): bool {
+		return $this->isAiGenerated;
+	}
+
 	public function hasHtmlMessage(): bool {
 		return $this->hasHtmlMessage;
 	}

lib/Service/MailTransmission.php

@@ -125,6 +125,10 @@ public function sendMessage(Account $account, LocalMessage $localMessage): void
 			$headers['In-Reply-To'] = $inReplyTo;
 		}
 
+		if ($localMessage->isAiGenerated()) {
+			$headers['X-AI-Generated'] = 'true';
+		}
+
 		if ($localMessage->getRequestMdn()) {
 			$headers[Horde_Mime_Mdn::MDN_HEADER] = $from->toHorde();
 		}

src/components/ThreadEnvelope.vue

@@ -86,6 +86,10 @@
 					<div v-if="hasChangedSubject" class="subline">
 						{{ cleanSubject }}
 					</div>
+					<div v-if="envelope.flags.aiGenerated" class="subline subline--ai-generated">
+						<AiIcon :size="14" />
+						<span>{{ t('mail', 'Contains AI generated content') }}</span>
+					</div>
 					<div v-if="showSubline" class="subline">
 						<span class="preview">
 							{{ isEncrypted ? t('mail', 'Encrypted message') : envelope.previewText }}
@@ -373,6 +377,7 @@ import { NcActionButton, NcButton } from '@nextcloud/vue'
 import { mapStores } from 'pinia'
 import NcActions from '@nextcloud/vue/components/NcActions'
 import NcActionText from '@nextcloud/vue/components/NcActionText'
+import AiIcon from '@nextcloud/vue/components/NcAssistantIcon'
 import ArchiveIcon from 'vue-material-design-icons/ArchiveArrowDownOutline.vue'
 import ChevronDownIcon from 'vue-material-design-icons/ChevronDown.vue'
 import ChevronUpIcon from 'vue-material-design-icons/ChevronUp.vue'
@@ -442,6 +447,7 @@ export default {
 		Error,
 		IconFavorite,
 		JunkIcon,
+		AiIcon,
 		MessageLoadingSkeleton,
 		MenuEnvelope,
 		Moment,
@@ -1477,4 +1483,10 @@ export default {
 		display: inline;
 		align-items: center;
 	}
+	.subline--ai-generated {
+		display: flex;
+		align-items: center;
+		gap: 4px;
+		opacity: 0.8;
+	}
 </style>