diff --git a/docs/chat.md b/docs/chat.md
index 161aceb1860..1909f2dff0b 100644
--- a/docs/chat.md
+++ b/docs/chat.md
@@ -500,6 +500,7 @@ See [OCP\RichObjectStrings\Definitions](https://github.com/nextcloud/server/blob
 | `status`        | string | Optional: Only available with `includeStatus=true` and for users with a set status                                                                                                                                                                                        |
 | `statusIcon`    | string | Optional: Only available with `includeStatus=true` and for users with a set status                                                                                                                                                                                        |
 | `statusMessage` | string | Optional: Only available with `includeStatus=true` and for users with a set status                                                                                                                                                                                        |
+| `details`       | string | Optional: Only provided for the "Everyone" option and can be used as a subline directly                                                                                                                                                                                   |
 
 ## System messages
 
diff --git a/lib/Chat/ChatManager.php b/lib/Chat/ChatManager.php
index 1c761d36f9c..fea3bcdff05 100644
--- a/lib/Chat/ChatManager.php
+++ b/lib/Chat/ChatManager.php
@@ -39,6 +39,7 @@
 use OCP\ICache;
 use OCP\ICacheFactory;
 use OCP\IDBConnection;
+use OCP\IL10N;
 use OCP\IRequest;
 use OCP\IUser;
 use OCP\Notification\IManager as INotificationManager;
@@ -97,6 +98,7 @@ public function __construct(
 		protected IReferenceManager $referenceManager,
 		protected ILimiter $rateLimiter,
 		protected IRequest $request,
+		protected IL10N $l,
 		protected LoggerInterface $logger,
 	) {
 		$this->cache = $cacheFactory->createDistributed(CachePrefix::CHAT_LAST_MESSAGE_ID);
@@ -961,12 +963,14 @@ public function addConversationNotify(array $results, string $search, Room $room
 			$roomDisplayName = $room->getDisplayName('');
 		}
 		if ($search === '' || $this->searchIsPartOfConversationNameOrAtAll($search, $roomDisplayName)) {
-			array_unshift($results, [
+			$participantCount = $this->participantService->getNumberOfUsers($room);
+			$results[] = [
 				'id' => 'all',
 				'label' => $roomDisplayName,
+				'details' => $this->l->n('All %n participant', 'All %n participants', $participantCount),
 				'source' => 'calls',
 				'mentionId' => 'all',
-			]);
+			];
 		}
 		return $results;
 	}
diff --git a/lib/ResponseDefinitions.php b/lib/ResponseDefinitions.php
index c1665b45dd3..0439896a6a0 100644
--- a/lib/ResponseDefinitions.php
+++ b/lib/ResponseDefinitions.php
@@ -56,6 +56,7 @@
  *     label: string,
  *     source: string,
  *     mentionId: string,
+ *     details: ?string,
  *     status: ?string,
  *     statusClearAt: ?int,
  *     statusIcon: ?string,
diff --git a/openapi-full.json b/openapi-full.json
index 757d0c1247c..2f2b1b90a4e 100644
--- a/openapi-full.json
+++ b/openapi-full.json
@@ -437,6 +437,7 @@
                     "label",
                     "source",
                     "mentionId",
+                    "details",
                     "status",
                     "statusClearAt",
                     "statusIcon",
@@ -455,6 +456,10 @@
                     "mentionId": {
                         "type": "string"
                     },
+                    "details": {
+                        "type": "string",
+                        "nullable": true
+                    },
                     "status": {
                         "type": "string",
                         "nullable": true
diff --git a/openapi.json b/openapi.json
index 86294c350d6..3c08d8beb51 100644
--- a/openapi.json
+++ b/openapi.json
@@ -378,6 +378,7 @@
                     "label",
                     "source",
                     "mentionId",
+                    "details",
                     "status",
                     "statusClearAt",
                     "statusIcon",
@@ -396,6 +397,10 @@
                     "mentionId": {
                         "type": "string"
                     },
+                    "details": {
+                        "type": "string",
+                        "nullable": true
+                    },
                     "status": {
                         "type": "string",
                         "nullable": true
diff --git a/src/components/NewMessage/NewMessage.vue b/src/components/NewMessage/NewMessage.vue
index 81e7679492c..ebd72c17077 100644
--- a/src/components/NewMessage/NewMessage.vue
+++ b/src/components/NewMessage/NewMessage.vue
@@ -911,7 +911,7 @@ export default {
 				if (possibleMention.source === 'calls') {
 					possibleMention.icon = 'icon-user-forced-white'
 					possibleMention.iconUrl = getConversationAvatarOcsUrl(this.token, isDarkTheme)
-					possibleMention.subline = t('spreed', 'Everyone')
+					possibleMention.subline = possibleMention?.details ? possibleMention.details : t('spreed', 'Everyone')
 				} else if (possibleMention.source === ATTENDEE.ACTOR_TYPE.GROUPS) {
 					possibleMention.icon = 'icon-group-forced-white'
 					possibleMention.subline = t('spreed', 'Group')
diff --git a/src/types/openapi/openapi-full.ts b/src/types/openapi/openapi-full.ts
index 60f16a8c050..51e0f631eed 100644
--- a/src/types/openapi/openapi-full.ts
+++ b/src/types/openapi/openapi-full.ts
@@ -1877,6 +1877,7 @@ export type components = {
             label: string;
             source: string;
             mentionId: string;
+            details: string | null;
             status: string | null;
             /** Format: int64 */
             statusClearAt: number | null;
diff --git a/src/types/openapi/openapi.ts b/src/types/openapi/openapi.ts
index 854ed99dc72..43dfd4134e3 100644
--- a/src/types/openapi/openapi.ts
+++ b/src/types/openapi/openapi.ts
@@ -1378,6 +1378,7 @@ export type components = {
             label: string;
             source: string;
             mentionId: string;
+            details: string | null;
             status: string | null;
             /** Format: int64 */
             statusClearAt: number | null;
diff --git a/tests/integration/features/bootstrap/FeatureContext.php b/tests/integration/features/bootstrap/FeatureContext.php
index 9cd7513e2fa..3d67880d186 100644
--- a/tests/integration/features/bootstrap/FeatureContext.php
+++ b/tests/integration/features/bootstrap/FeatureContext.php
@@ -3080,8 +3080,13 @@ public function userGetsTheFollowingCandidateMentionsInRoomFor($user, $identifie
 			Assert::assertEmpty($mentions);
 			return;
 		}
+		$expected = $formData->getHash();
+		if (empty($expected)) {
+			Assert::assertEmpty($mentions);
+			return;
+		}
 
-		Assert::assertCount(count($formData->getHash()), $mentions, 'Mentions count does not match' . "\n" . json_encode($mentions, JSON_PRETTY_PRINT));
+		Assert::assertCount(count($expected), $mentions, 'Mentions count does not match' . "\n" . json_encode($mentions, JSON_PRETTY_PRINT));
 
 		usort($mentions, function ($a, $b) {
 			if ($a['source'] === $b['source']) {
@@ -3090,7 +3095,6 @@ public function userGetsTheFollowingCandidateMentionsInRoomFor($user, $identifie
 			return $a['source'] <=> $b['source'];
 		});
 
-		$expected = $formData->getHash();
 		usort($expected, function ($a, $b) {
 			if ($a['source'] === $b['source']) {
 				return $a['label'] <=> $b['label'];
@@ -3098,6 +3102,8 @@ public function userGetsTheFollowingCandidateMentionsInRoomFor($user, $identifie
 			return $a['source'] <=> $b['source'];
 		});
 
+		$checkDetails = array_key_exists('details', $expected[0]);
+
 		foreach ($expected as $key => $row) {
 			if ($row['id'] === 'GUEST_ID') {
 				Assert::assertMatchesRegularExpression('/^guest\/[0-9a-f]{40}$/', $mentions[$key]['id']);
@@ -3124,6 +3130,11 @@ public function userGetsTheFollowingCandidateMentionsInRoomFor($user, $identifie
 				unset($row['avatar']);
 			}
 			unset($mentions[$key]['avatar']);
+			if (!$checkDetails) {
+				unset($mentions[$key]['details']);
+			} elseif (empty($row['details'])) {
+				unset($row['details']);
+			}
 			Assert::assertEquals($row, $mentions[$key]);
 		}
 	}
diff --git a/tests/integration/features/chat-1/mentions.feature b/tests/integration/features/chat-1/mentions.feature
index c3140dddf35..78d32f8167c 100644
--- a/tests/integration/features/chat-1/mentions.feature
+++ b/tests/integration/features/chat-1/mentions.feature
@@ -48,8 +48,8 @@ Feature: chat/mentions
       | roomType | 2 |
       | roomName | room |
     Then user "participant1" gets the following candidate mentions in room "group room" for "" with 200
-      | id           | label                    | source | mentionId    |
-      | all          | room                     | calls  | all          |
+      | id           | label                    | source | mentionId    | details           |
+      | all          | room                     | calls  | all          | All 1 participant |
 
   Scenario: get mentions in a group room
     When user "participant1" creates room "group room" (v4)
@@ -223,7 +223,6 @@ Feature: chat/mentions
       | id           | label                    | source | mentionId    |
       | GUEST_ID     | FooBar                   | guests | GUEST_ID     |
     And user "guest1" gets the following candidate mentions in room "public room" for "oob" with 200
-      | id           | label                    | source | mentionId    |
     And user "guest2" gets the following candidate mentions in room "public room" for "oob" with 200
       | id           | label                    | source | mentionId    |
       | GUEST_ID     | FooBar                   | guests | GUEST_ID     |
diff --git a/tests/php/Chat/ChatManagerTest.php b/tests/php/Chat/ChatManagerTest.php
index 6160e01b8c9..07bbcdfdd42 100644
--- a/tests/php/Chat/ChatManagerTest.php
+++ b/tests/php/Chat/ChatManagerTest.php
@@ -28,6 +28,7 @@
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\ICacheFactory;
 use OCP\IDBConnection;
+use OCP\IL10N;
 use OCP\IRequest;
 use OCP\IUser;
 use OCP\Notification\IManager as INotificationManager;
@@ -58,6 +59,7 @@ class ChatManagerTest extends TestCase {
 	protected ILimiter&MockObject $rateLimiter;
 	protected IRequest&MockObject $request;
 	protected LoggerInterface&MockObject $logger;
+	protected IL10N&MockObject $l;
 	protected ?ChatManager $chatManager = null;
 
 	public function setUp(): void {
@@ -77,8 +79,15 @@ public function setUp(): void {
 		$this->referenceManager = $this->createMock(IReferenceManager::class);
 		$this->rateLimiter = $this->createMock(ILimiter::class);
 		$this->request = $this->createMock(IRequest::class);
+		$this->l = $this->createMock(IL10N::class);
 		$this->logger = $this->createMock(LoggerInterface::class);
 
+		$this->l->method('n')
+			->willReturnCallback(function (string $singular, string $plural, int $count, array $parameters = []) {
+				$text = $count === 1 ? $singular : $plural;
+				return vsprintf(str_replace('%n', (string) $count, $text), $parameters);
+			});
+
 		$this->chatManager = $this->getManager();
 	}
 
@@ -108,6 +117,7 @@ protected function getManager(array $methods = []): ChatManager {
 					$this->referenceManager,
 					$this->rateLimiter,
 					$this->request,
+					$this->l,
 					$this->logger,
 				])
 				->onlyMethods($methods)
@@ -131,6 +141,7 @@ protected function getManager(array $methods = []): ChatManager {
 			$this->referenceManager,
 			$this->rateLimiter,
 			$this->request,
+			$this->l,
 			$this->logger,
 		);
 	}
@@ -690,7 +701,8 @@ public static function dataAddConversationNotify(): array {
 				'',
 				['getType' => Room::TYPE_ONE_TO_ONE],
 				[],
-				[]
+				null,
+				[],
 			],
 			[
 				'',
@@ -699,13 +711,15 @@ public static function dataAddConversationNotify(): array {
 					'actor_type' => Attendee::ACTOR_USERS,
 					'actor_id' => 'user',
 				])],
-				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all']]
+				324,
+				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all', 'details' => 'All 324 participants']]
 			],
 			[
 				'',
 				['getMentionPermissions' => 1],
 				['hasModeratorPermissions' => false],
-				[]
+				null,
+				[],
 			],
 			[
 				'all',
@@ -714,7 +728,8 @@ public static function dataAddConversationNotify(): array {
 					'actor_type' => Attendee::ACTOR_USERS,
 					'actor_id' => 'user',
 				])],
-				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all']]
+				1,
+				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all', 'details' => 'All 1 participant']],
 			],
 			[
 				'all',
@@ -726,7 +741,8 @@ public static function dataAddConversationNotify(): array {
 					]),
 					'hasModeratorPermissions' => true,
 				],
-				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all']]
+				8,
+				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all', 'details' => 'All 8 participants']],
 			],
 			[
 				'here',
@@ -735,7 +751,8 @@ public static function dataAddConversationNotify(): array {
 					'actor_type' => Attendee::ACTOR_GUESTS,
 					'actor_id' => 'guest',
 				])],
-				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all']]
+				12,
+				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all', 'details' => 'All 12 participants']],
 			],
 		];
 	}
@@ -743,7 +760,7 @@ public static function dataAddConversationNotify(): array {
 	/**
 	 * @dataProvider dataAddConversationNotify
 	 */
-	public function testAddConversationNotify(string $search, array $roomMocks, array $participantMocks, array $expected): void {
+	public function testAddConversationNotify(string $search, array $roomMocks, array $participantMocks, ?int $totalCount, array $expected): void {
 		$room = $this->createMock(Room::class);
 		foreach ($roomMocks as $method => $return) {
 			$room->expects($this->once())
@@ -758,6 +775,11 @@ public function testAddConversationNotify(string $search, array $roomMocks, arra
 				->willReturn($return);
 		}
 
+		if ($totalCount !== null) {
+			$this->participantService->method('getNumberOfUsers')
+				->willReturn($totalCount);
+		}
+
 		$actual = $this->chatManager->addConversationNotify([], $search, $room, $participant);
 		$this->assertEquals($expected, $actual);
 	}