diff --git a/cypress/e2e/cardFeatures.js b/cypress/e2e/cardFeatures.js
index def7e258db..1fa0209ad7 100644
--- a/cypress/e2e/cardFeatures.js
+++ b/cypress/e2e/cardFeatures.js
@@ -270,12 +270,13 @@ describe('Card', function () {
 
 		it('Shows the modal with the editor', () => {
 			cy.get('.card:contains("Hello world")').should('be.visible').click()
-			cy.intercept({ method: 'PUT', url: '**/ocs/v2.php/apps/deck/api/v1.0/cards/*' }).as('save')
+			cy.intercept({ method: 'POST', url: '**/apps/text/session/*/save' }).as('save')
 			cy.get('.modal__card').should('be.visible')
 			cy.get('.app-sidebar-header__mainname').contains('Hello world')
 			cy.get('.modal__card .ProseMirror h1').contains('Hello world').should('be.visible')
 			cy.get('.modal__card .ProseMirror h1')
 				.click()
+				.parent()
 				.type(' writing more text{enter}- List item{enter}with entries{enter}{enter}Paragraph')
 			cy.wait('@save', { timeout: 7000 })
 
@@ -284,7 +285,7 @@ describe('Card', function () {
 
 			// Scroll to the bottom to ensure all content is loaded and visible
 			cy.get('.modal__card .app-sidebar-tabs, .modal__card .app-sidebar__tab--active').first().scrollTo('bottom', { ensureScrollable: false })
-			cy.contains('.modal__card .ProseMirror p', 'Paragraph').scrollIntoView().should('be.visible')
+			cy.contains('.modal__card .ProseMirror p', 'Paragraph').should('be.visible')
 
 			cy.get('.modal__card .ProseMirror h1').contains('Hello world writing more text').should('be.visible')
 			cy.get('.modal__card .ProseMirror li').eq(0).contains('List item').should('be.visible')
@@ -298,7 +299,7 @@ describe('Card', function () {
 			cy.get('.card:contains("Hello world")').should('be.visible').click()
 			cy.get('.modal__card').should('be.visible')
 			cy.get('.modal__card .ProseMirror h1')
-				.click()
+				.click().parent()
 				.type('{enter}/create')
 			cy.get('.suggestion-list__item.is-selected').should('be.visible').contains('Create a new deck card')
 			cy.get('.suggestion-list__item.is-selected .link-picker__item').click()
diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index fa1df26ff0..bd1399b7e9 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -25,6 +25,7 @@
 use OCA\Deck\Event\CardCreatedEvent;
 use OCA\Deck\Event\CardDeletedEvent;
 use OCA\Deck\Event\CardUpdatedEvent;
+use OCA\Deck\Event\RegisterTextContextEventListener;
 use OCA\Deck\Event\SessionClosedEvent;
 use OCA\Deck\Event\SessionCreatedEvent;
 use OCA\Deck\Federation\DeckFederationProvider;
@@ -37,6 +38,7 @@
 use OCA\Deck\Listeners\ResourceAdditionalScriptsListener;
 use OCA\Deck\Listeners\ResourceListener;
 use OCA\Deck\Listeners\ResourceTypeRegisterListener;
+use OCA\Deck\Listeners\TextDocumentContentListener;
 use OCA\Deck\Middleware\DefaultBoardMiddleware;
 use OCA\Deck\Middleware\ExceptionMiddleware;
 use OCA\Deck\Middleware\FederationMiddleware;
@@ -52,7 +54,9 @@
 use OCA\Deck\Sharing\Listener;
 use OCA\Deck\Teams\DeckTeamResourceProvider;
 use OCA\Deck\UserMigration\DeckMigrator;
+use OCA\Text\Event\DocumentContentUpdated;
 use OCA\Text\Event\LoadEditor;
+use OCA\Text\Event\RegisterContextEvent;
 use OCP\AppFramework\App;
 use OCP\AppFramework\Bootstrap\IBootContext;
 use OCP\AppFramework\Bootstrap\IBootstrap;
@@ -106,6 +110,12 @@ public function boot(IBootContext $context): void {
 		$context->injectFn($this->registerCommentsEntity(...));
 		$context->injectFn($this->registerCollaborationResources(...));
 
+		if (class_exists(DocumentContentUpdated::class)) {
+			$context->injectFn(function (IEventDispatcher $eventDispatcher) {
+				$eventDispatcher->addServiceListener(CardUpdatedEvent::class, TextDocumentContentListener::class);
+			});
+		}
+
 		$context->injectFn(function (IManager $shareManager) {
 			$shareManager->registerShareProvider(DeckShareProvider::class);
 		});
@@ -191,6 +201,8 @@ public function register(IRegistrationContext $context): void {
 		$context->registerTeamResourceProvider(DeckTeamResourceProvider::class);
 
 		$context->registerUserMigrator(DeckMigrator::class);
+
+		$context->registerEventListener(RegisterContextEvent::class, RegisterTextContextEventListener::class);
 	}
 
 	public function registerCommentsEntity(IEventDispatcher $eventDispatcher): void {
diff --git a/lib/Event/RegisterTextContextEventListener.php b/lib/Event/RegisterTextContextEventListener.php
new file mode 100644
index 0000000000..4a9bced537
--- /dev/null
+++ b/lib/Event/RegisterTextContextEventListener.php
@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OCA\Deck\Event;
+
+use OCA\Deck\Provider\TextContextProviderFactory;
+use OCA\Text\Event\RegisterContextEvent;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+
+/** @template-implements IEventListener<Event|RegisterContextEvent> */
+class RegisterTextContextEventListener implements IEventListener {
+	public function __construct(
+		private readonly TextContextProviderFactory $textContextProviderFactory,
+	) {
+	}
+	public function handle(Event $event): void {
+		if (!$event instanceof RegisterContextEvent) {
+			return;
+		}
+
+		$event->getContextManager()->registerContext(
+			'deck_card',
+			TextContextProviderFactory::class
+		);
+	}
+}
diff --git a/lib/Listeners/TextDocumentContentListener.php b/lib/Listeners/TextDocumentContentListener.php
new file mode 100644
index 0000000000..8836651aaf
--- /dev/null
+++ b/lib/Listeners/TextDocumentContentListener.php
@@ -0,0 +1,46 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OCA\Deck\Listeners;
+
+use OCA\Deck\Event\CardUpdatedEvent;
+use OCA\Deck\Provider\TextContextProviderFactory;
+use OCA\Text\Event\DocumentContentUpdated;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\EventDispatcher\IEventListener;
+
+/**
+ * Tells Text that a card description changed so it can resolve open editing sessions.
+ *
+ * @template-implements IEventListener<Event|CardUpdatedEvent>
+ */
+class TextDocumentContentListener implements IEventListener {
+	public function __construct(
+		private readonly IEventDispatcher $eventDispatcher,
+		private readonly TextContextProviderFactory $contextFactory,
+	) {
+	}
+
+	public function handle(Event $event): void {
+		if (!($event instanceof CardUpdatedEvent) || !class_exists(DocumentContentUpdated::class)) {
+			return;
+		}
+
+		$before = $event->getCardBefore();
+		$card = $event->getCard();
+		if ($before === null || $before->getDescription() === $card->getDescription()) {
+			return;
+		}
+
+		$this->eventDispatcher->dispatchTyped(
+			new DocumentContentUpdated($this->contextFactory->buildForCard($card->getId()))
+		);
+	}
+}
diff --git a/lib/Provider/TextContextProvider.php b/lib/Provider/TextContextProvider.php
new file mode 100644
index 0000000000..65cfa3ab28
--- /dev/null
+++ b/lib/Provider/TextContextProvider.php
@@ -0,0 +1,134 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2019 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Deck\Provider;
+
+use OC\Security\SecureRandom;
+use OCA\Deck\Db\Acl;
+use OCA\Deck\Db\Card;
+use OCA\Deck\Db\CardMapper;
+use OCA\Deck\NoPermissionException;
+use OCA\Deck\Service\CardService;
+use OCA\Deck\Service\PermissionService;
+use OCA\Text\Context\IContext;
+use OCA\Text\Context\SessionInfo;
+use OCA\Text\Db\Document;
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\Files\File;
+use OCP\Files\NotFoundException;
+use OCP\Files\NotPermittedException;
+
+class TextContextProvider implements IContext {
+	public const CONTEXT_TYPE = 'deck_card';
+
+	public function __construct(
+		private readonly SecureRandom $secureRandom,
+		private readonly CardService $cardService,
+		private readonly CardMapper $cardMapper,
+		private readonly PermissionService $permissionService,
+		private readonly string $userId,
+		private readonly int $cardId,
+	) {
+	}
+	public function getId(): int {
+		return $this->cardId;
+	}
+
+	public function getType(): string {
+		return self::CONTEXT_TYPE;
+	}
+
+	public function toString(): string {
+		return $this->getType() . ' (' . $this->getId() . ')';
+	}
+
+	public function buildDocument(): Document {
+		$document = new Document();
+		$document->setContextType($this->getType());
+		$document->setContextId($this->getId());
+		$document->setLastSavedVersion(0);
+		$document->setLastSavedVersionTime($this->getLastModified());
+		$document->setLastSavedVersionEtag($this->secureRandom->generate(6));
+
+		$document->setChecksum($this->computeChecksum());
+		$document->setBaseVersionEtag(uniqid());
+		return $document;
+	}
+
+	public function prepareSession(): SessionInfo {
+		$readonly = !$this->permissionService->checkPermission($this->cardMapper, $this->cardId, Acl::PERMISSION_EDIT, $this->userId);
+		return new SessionInfo(
+			readOnly: $readonly,
+			lock: null,
+			canAttachFiles: false,
+		);
+	}
+
+	public function isReadOnly(): bool {
+		return !$this->permissionService->checkPermission($this->cardMapper, $this->cardId, Acl::PERMISSION_EDIT, $this->userId);
+	}
+
+	public function updateDocument(Document $document): void {
+		$document->setChecksum($this->computeChecksum());
+		$document->setLastSavedVersionTime($this->getLastModified());
+	}
+
+	/**
+	 * @throws NotFoundException
+	 * @throws NotPermittedException
+	 */
+	private function findCard(): Card {
+		try {
+			return $this->cardService->find($this->cardId);
+		} catch (DoesNotExistException $e) {
+			throw new NotFoundException($e->getMessage(), 0, $e);
+		} catch (NoPermissionException $e) {
+			throw new NotPermittedException($e->getMessage(), 0, $e);
+		}
+	}
+
+	/**
+	 * @throws NotFoundException
+	 * @throws NotPermittedException
+	 */
+	private function getLastModified(): int {
+		$card = $this->findCard();
+		return (int)($card->getLastModified() ?: time());
+	}
+
+	public function getFile(): ?File {
+		return null;
+	}
+
+	/**
+	 * @throws NotFoundException
+	 * @throws NotPermittedException
+	 */
+	public function loadContent(): ?string {
+		$card = $this->findCard();
+		return $card->getDescription();
+	}
+
+	public function cleanup(): void {
+	}
+
+	public function save(string $content, callable $afterSave): void {
+		$this->cardService->updateDescription($this->cardId, $content);
+		$afterSave();
+	}
+
+	/**
+	 * @throws NotFoundException
+	 * @throws NotPermittedException
+	 */
+	private function computeChecksum(): string {
+		$card = $this->findCard();
+		return hash('crc32', $card->getDescription());
+	}
+
+}
diff --git a/lib/Provider/TextContextProviderFactory.php b/lib/Provider/TextContextProviderFactory.php
new file mode 100644
index 0000000000..fd4b78c68c
--- /dev/null
+++ b/lib/Provider/TextContextProviderFactory.php
@@ -0,0 +1,43 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Deck\Provider;
+
+use OC\Security\SecureRandom;
+use OCA\Deck\Db\CardMapper;
+use OCA\Deck\Service\CardService;
+use OCA\Deck\Service\PermissionService;
+use OCA\Text\Context\IContext;
+use OCA\Text\Context\IContextFactory;
+use OCP\IUser;
+use OCP\Share\IShare;
+
+class TextContextProviderFactory implements IContextFactory {
+	public function __construct(
+		private readonly SecureRandom $secureRandom,
+		private readonly CardService $cardService,
+		private readonly CardMapper $cardMapper,
+		private readonly PermissionService $permissionService,
+		private readonly string $userId,
+	) {
+	}
+
+	public function build(IUser|IShare $auth, string $type, int $id): IContext {
+		return $this->buildForCard($id);
+	}
+
+	public function buildForCard(int $cardId): TextContextProvider {
+		return new TextContextProvider(
+			secureRandom: $this->secureRandom,
+			cardService: $this->cardService,
+			cardMapper: $this->cardMapper,
+			permissionService: $this->permissionService,
+			userId: $this->userId,
+			cardId: $cardId,
+		);
+	}
+}
diff --git a/lib/Service/CardService.php b/lib/Service/CardService.php
index 7ebc8d8a6f..695a249d68 100644
--- a/lib/Service/CardService.php
+++ b/lib/Service/CardService.php
@@ -284,21 +284,7 @@ public function update(int $id, string $title, int $stackId, string $type, strin
 		}
 
 		$changes = new ChangeSet($card);
-		if ($card->getLastEditor() !== $this->userId && $card->getLastEditor() !== null) {
-			$this->activityManager->triggerEvent(
-				ActivityManager::DECK_OBJECT_CARD,
-				$card,
-				ActivityManager::SUBJECT_CARD_UPDATE_DESCRIPTION,
-				[
-					'before' => $card->getDescriptionPrev(),
-					'after' => $card->getDescription()
-				],
-				$card->getLastEditor()
-			);
-
-			$card->setDescriptionPrev($card->getDescription());
-			$card->setLastEditor($this->userId);
-		}
+		$this->trackDescriptionEditor($card);
 		$card->setTitle($title);
 		$card->setStackId($stackId);
 		$card->setType($type);
@@ -441,6 +427,61 @@ public function rename(int $id, string $title): Card {
 		return $update;
 	}
 
+	/**
+	 * Update only the description, leaving all other card fields untouched.
+	 *
+	 * @throws StatusException
+	 * @throws \OCA\Deck\NoPermissionException
+	 * @throws \OCP\AppFramework\Db\DoesNotExistException
+	 * @throws \OCP\AppFramework\Db\MultipleObjectsReturnedException
+	 * @throws BadRequestException
+	 */
+	public function updateDescription(int $id, string $description): Card {
+		$this->cardServiceValidator->check(compact('id'));
+
+		$this->permissionService->checkPermission($this->cardMapper, $id, Acl::PERMISSION_EDIT);
+		if ($this->boardService->isArchived($this->cardMapper, $id)) {
+			throw new StatusException('Operation not allowed. This board is archived.');
+		}
+		$card = $this->cardMapper->find($id);
+		if ($card->getArchived()) {
+			throw new StatusException('Operation not allowed. This card is archived.');
+		}
+		$changes = new ChangeSet($card);
+		$this->trackDescriptionEditor($card);
+		if ($card->getDescriptionPrev() === null) {
+			$card->setDescriptionPrev($card->getDescription());
+		}
+		$card->setDescription($description);
+		$update = $this->cardMapper->update($card);
+		$this->changeHelper->cardChanged($card->getId());
+
+		$this->eventDispatcher->dispatchTyped(new CardUpdatedEvent($card, $changes->getBefore()));
+
+		return $update;
+	}
+
+	/**
+	 * Publish description changes as activity
+	 */
+	private function trackDescriptionEditor(Card $card): void {
+		if ($card->getLastEditor() !== $this->userId && $card->getLastEditor() !== null) {
+			$this->activityManager->triggerEvent(
+				ActivityManager::DECK_OBJECT_CARD,
+				$card,
+				ActivityManager::SUBJECT_CARD_UPDATE_DESCRIPTION,
+				[
+					'before' => $card->getDescriptionPrev(),
+					'after' => $card->getDescription()
+				],
+				$card->getLastEditor()
+			);
+
+			$card->setDescriptionPrev($card->getDescription());
+			$card->setLastEditor($this->userId);
+		}
+	}
+
 	/**
 	 * @return list<Card>
 	 * @throws StatusException
diff --git a/src/components/card/Description.vue b/src/components/card/Description.vue
index 8da0a60195..6ae9252926 100644
--- a/src/components/card/Description.vue
+++ b/src/components/card/Description.vue
@@ -7,8 +7,8 @@
 	<div data-test="description">
 		<h5>
 			{{ t('deck', 'Description') }}
-			<span v-if="descriptionLastEdit && !descriptionSaving">{{ t('deck', '(Unsaved)') }}</span>
-			<span v-if="descriptionSaving">{{ t('deck', '(Saving…)') }}</span>
+			<span v-if="!collaborative && descriptionLastEdit && !descriptionSaving">{{ t('deck', '(Unsaved)') }}</span>
+			<span v-if="!collaborative && descriptionSaving">{{ t('deck', '(Saving…)') }}</span>
 			<a v-if="!textAppAvailable"
 				:title="t('deck', 'Formatting help')"
 				href="https://deck.readthedocs.io/en/latest/Markdown/"
@@ -76,6 +76,7 @@ import { generateUrl } from '@nextcloud/router'
 import { showWarning } from '@nextcloud/dialogs'
 import PaperclipIcon from 'vue-material-design-icons/Paperclip.vue'
 import { mapState, mapActions } from 'pinia'
+import VueEasymde from 'vue-easymde'
 import { useCardStore } from '../../stores/card.js'
 import { useSettingsStore } from '../../stores/settings.js'
 
@@ -94,7 +95,7 @@ markdownIt.use(MarkdownItLinkAttributes, {
 export default {
 	name: 'Description',
 	components: {
-		VueEasymde: () => import('vue-easymde/dist/VueEasyMDE.common.js'),
+		VueEasymde,
 		NcActions,
 		NcActionButton,
 		NcModal,
@@ -118,7 +119,7 @@ export default {
 	emits: ['change'],
 	data() {
 		return {
-			textAppAvailable: !!window.OCA?.Text?.createEditor,
+			textAppAvailable: !!window.OCA?.Text?.createCollaborativeEditor,
 			editor: null,
 			keyExitState: 0,
 			descriptionOld: '',
@@ -142,6 +143,12 @@ export default {
 	},
 	computed: {
 		...mapState(useSettingsStore, ['hasCardSaveError']),
+
+		// Only persisted cards can have a collaborative Text session
+		collaborative() {
+			return this.textAppAvailable && !!this.card?.id
+		},
+
 		mimetypeForAttachment() {
 			return (mimetype) => {
 				const url = OC.MimeType.getIconUrl(mimetype)
@@ -176,21 +183,27 @@ export default {
 	},
 	watch: {
 		card(newCard) {
+			if (this.collaborative) {
+				return
+			}
 			if (newCard.description !== this.descriptionOld) {
 				clearTimeout(this.descriptionSaveTimeout)
 				this.descriptionLastEdit = 0
 
 				this.descriptionOld = newCard.description
 				this.description = newCard.description
-				if (this.editor) {
-					this.editor.setContent(this.description)
-				}
 				showWarning(t('deck', 'The description has been changed by another user.'), { timeout: 3000 })
 			}
 		},
 	},
 	mounted() {
-		this.setupEditor()
+		if (!this.collaborative) {
+			this.descriptionOld = this.card.description
+			this.description = this.card.description
+		}
+		if (this.textAppAvailable) {
+			this.setupEditor()
+		}
 	},
 	async beforeUnmount() {
 		await this.destroyEditor()
@@ -202,16 +215,18 @@ export default {
 		...mapActions(useSettingsStore, ['setHasCardSaveError']),
 		async setupEditor() {
 			await this.destroyEditor()
-			this.descriptionLastEdit = 0
-			this.descriptionOld = this.card.description
-			this.description = this.card.description
-			this.editor = await window.OCA.Text.createEditor({
+			if (this.collaborative) {
+				this.editor = await window.OCA.Text.createCollaborativeEditor({
+					context: { type: 'deck_card', id: this.card.id },
+					el: this.$refs.editor,
+					readOnly: !this.canEdit,
+				})
+				return
+			}
+			this.editor = await window.OCA.Text.createMarkdownContentEditor({
 				el: this.$refs.editor,
 				content: this.card.description,
 				readOnly: !this.canEdit,
-				onLoaded: () => {
-					this.descriptionLastEdit = 0
-				},
 				onUpdate: ({ markdown }) => {
 					if (this.description === markdown) {
 						return
@@ -219,14 +234,14 @@ export default {
 					this.description = markdown
 					this.updateDescription()
 				},
-				onFileInsert: () => {
-					this.showAttachmentModal()
-				},
 			})
 
 		},
 		async destroyEditor() {
-			await this.saveDescription()
+			clearTimeout(this.descriptionSaveTimeout)
+			if (!this.collaborative) {
+				await this.saveDescription()
+			}
 			try {
 				this?.editor?.destroy()
 			} catch (e) {
@@ -287,8 +302,8 @@ export default {
 				const newContent = descString + '\n' + attachmentString
 				this.$refs.markdownEditor.easymde.value(newContent)
 				this.description = newContent
+				this.updateDescription()
 			}
-			this.updateDescription()
 			this.modalShow = false
 		},
 		clickedPreview(e) {
diff --git a/tests/stub.phpstub b/tests/stub.phpstub
index 73673f72e5..7d71caadc0 100644
--- a/tests/stub.phpstub
+++ b/tests/stub.phpstub
@@ -732,4 +732,62 @@ namespace OCA\NotifyPush\Queue {
 
 namespace OCA\Text\Event {
 	class LoadEditor extends \OCP\EventDispatcher\Event {}
+
+	class RegisterContextEvent extends \OCP\EventDispatcher\Event {
+		public function getContextManager(): \OCA\Text\Context\ContextManager {
+		}
+	}
+
+	class DocumentContentUpdated extends \OCP\EventDispatcher\Event {
+		public function __construct(\OCA\Text\Context\IContext $context) {
+		}
+	}
+}
+
+namespace OCA\Text\Context {
+	class ContextManager {
+		public function registerContext(string $type, string $factoryClass): void {
+		}
+	}
+
+	class SessionInfo {
+		public ?string $content = null;
+
+		public function __construct(
+			public bool $readOnly,
+			public bool $canAttachFiles,
+			public ?\OCP\Files\Lock\ILock $lock,
+		) {
+		}
+	}
+
+	interface IContext {
+		public function getId(): int;
+		public function getType(): string;
+		public function toString(): string;
+		public function buildDocument(): \OCA\Text\Db\Document;
+		public function prepareSession(): SessionInfo;
+		public function isReadOnly(): bool;
+		public function updateDocument(\OCA\Text\Db\Document $document): void;
+		public function getFile(): ?\OCP\Files\File;
+		public function loadContent(): ?string;
+		public function save(string $content, callable $afterSave): void;
+		public function cleanup(): void;
+	}
+
+	interface IContextFactory {
+		public function build(\OCP\IUser|\OCP\Share\IShare $auth, string $type, int $id): IContext;
+	}
+}
+
+namespace OCA\Text\Db {
+	/**
+	 * @method void setContextType(string $contextType)
+	 * @method void setContextId(int $contextId)
+	 * @method void setLastSavedVersion(int $version)
+	 * @method void setLastSavedVersionTime(int $time)
+	 * @method void setChecksum(?string $checksum)
+	 */
+	class Document extends \OCP\AppFramework\Db\Entity {
+	}
 }
diff --git a/tests/unit/Listeners/TextDocumentContentListenerTest.php b/tests/unit/Listeners/TextDocumentContentListenerTest.php
new file mode 100644
index 0000000000..fcf6f86d01
--- /dev/null
+++ b/tests/unit/Listeners/TextDocumentContentListenerTest.php
@@ -0,0 +1,56 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Deck\Listeners;
+
+use OCA\Deck\Db\Card;
+use OCA\Deck\Event\CardUpdatedEvent;
+use OCA\Deck\Provider\TextContextProvider;
+use OCA\Deck\Provider\TextContextProviderFactory;
+use OCA\Text\Event\DocumentContentUpdated;
+use OCP\EventDispatcher\IEventDispatcher;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+class TextDocumentContentListenerTest extends TestCase {
+	private IEventDispatcher&MockObject $dispatcher;
+	private TextContextProviderFactory&MockObject $factory;
+	private TextDocumentContentListener $listener;
+
+	protected function setUp(): void {
+		parent::setUp();
+		if (!class_exists(DocumentContentUpdated::class)) {
+			$this->markTestSkipped('Text app not available');
+		}
+		$this->dispatcher = $this->createMock(IEventDispatcher::class);
+		$this->factory = $this->createMock(TextContextProviderFactory::class);
+		$this->listener = new TextDocumentContentListener($this->dispatcher, $this->factory);
+	}
+
+	private function event(string $before, string $after): CardUpdatedEvent {
+		$old = new Card();
+		$old->setId(5);
+		$old->setDescription($before);
+		$new = new Card();
+		$new->setId(5);
+		$new->setDescription($after);
+		return new CardUpdatedEvent($new, $old);
+	}
+
+	public function testDispatchesOnDescriptionChange(): void {
+		$context = $this->createMock(TextContextProvider::class);
+		$this->factory->expects($this->once())->method('buildForCard')->with(5)->willReturn($context);
+		$this->dispatcher->expects($this->once())->method('dispatchTyped')
+			->with($this->callback(fn ($e) => $e instanceof DocumentContentUpdated && $e->getContext() === $context));
+		$this->listener->handle($this->event('a', 'b'));
+	}
+
+	public function testIgnoresUnchangedDescription(): void {
+		$this->dispatcher->expects($this->never())->method('dispatchTyped');
+		$this->listener->handle($this->event('a', 'a'));
+	}
+}
diff --git a/tests/unit/Provider/TextContextProviderTest.php b/tests/unit/Provider/TextContextProviderTest.php
new file mode 100644
index 0000000000..72f0408fd2
--- /dev/null
+++ b/tests/unit/Provider/TextContextProviderTest.php
@@ -0,0 +1,78 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Deck\Provider;
+
+use OC\Security\SecureRandom;
+use OCA\Deck\Db\Card;
+use OCA\Deck\Db\CardMapper;
+use OCA\Deck\NoPermissionException;
+use OCA\Deck\Service\CardService;
+use OCA\Deck\Service\PermissionService;
+use OCA\Text\Context\IContext;
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\Files\NotFoundException;
+use OCP\Files\NotPermittedException;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+class TextContextProviderTest extends TestCase {
+	private CardService&MockObject $cardService;
+	private TextContextProvider $provider;
+
+	protected function setUp(): void {
+		parent::setUp();
+		if (!interface_exists(IContext::class)) {
+			$this->markTestSkipped('Text app not available');
+		}
+		$this->cardService = $this->createMock(CardService::class);
+		$this->provider = new TextContextProvider(
+			$this->createMock(SecureRandom::class),
+			$this->cardService,
+			$this->createMock(CardMapper::class),
+			$this->createMock(PermissionService::class),
+			'admin',
+			5,
+		);
+	}
+
+	public function testLoadContent(): void {
+		$card = new Card();
+		$card->setDescription('hello');
+		$this->cardService->method('find')->with(5)->willReturn($card);
+
+		$this->assertSame('hello', $this->provider->loadContent());
+	}
+
+	public function testLoadContentCardMissing(): void {
+		$this->cardService->method('find')->willThrowException(new DoesNotExistException('missing'));
+
+		$this->expectException(NotFoundException::class);
+		$this->provider->loadContent();
+	}
+
+	public function testLoadContentNoPermission(): void {
+		$this->cardService->method('find')->willThrowException(new NoPermissionException('denied'));
+
+		$this->expectException(NotPermittedException::class);
+		$this->provider->loadContent();
+	}
+
+	public function testBuildDocumentCardMissing(): void {
+		$this->cardService->method('find')->willThrowException(new DoesNotExistException('missing'));
+
+		$this->expectException(NotFoundException::class);
+		$this->provider->buildDocument();
+	}
+
+	public function testBuildDocumentNoPermission(): void {
+		$this->cardService->method('find')->willThrowException(new NoPermissionException('denied'));
+
+		$this->expectException(NotPermittedException::class);
+		$this->provider->buildDocument();
+	}
+}
diff --git a/tests/unit/Service/CardServiceTest.php b/tests/unit/Service/CardServiceTest.php
index 94a96a7a98..5666718bb0 100644
--- a/tests/unit/Service/CardServiceTest.php
+++ b/tests/unit/Service/CardServiceTest.php
@@ -36,6 +36,7 @@
 use OCA\Deck\Db\LabelMapper;
 use OCA\Deck\Db\Stack;
 use OCA\Deck\Db\StackMapper;
+use OCA\Deck\Event\CardUpdatedEvent;
 use OCA\Deck\Model\CardDetails;
 use OCA\Deck\Model\OptionalNullableValue;
 use OCA\Deck\Notification\NotificationHelper;
@@ -604,6 +605,40 @@ public function testRenameArchived() {
 		$this->cardService->rename(123, 'newtitle');
 	}
 
+	public function testUpdateDescriptionKeepsOtherFields() {
+		$duedate = new \DateTime('2017-01-01T00:00:00+00:00');
+		$startdate = new \DateTime('2016-12-01T00:00:00+00:00');
+		$done = new \DateTime('2017-01-02T00:00:00+00:00');
+		$card = new Card();
+		$card->setId(123);
+		$card->setTitle('title');
+		$card->setDescription('old');
+		$card->setArchived(false);
+		$card->setDuedate($duedate);
+		$card->setStartdate($startdate);
+		$card->setDone($done);
+		$this->cardMapper->expects($this->once())->method('find')->willReturn($card);
+		$this->cardMapper->expects($this->once())->method('update')->willReturnArgument(0);
+		$this->eventDispatcher->expects($this->once())->method('dispatchTyped')
+			->with($this->isInstanceOf(CardUpdatedEvent::class));
+		$actual = $this->cardService->updateDescription(123, 'new');
+		$this->assertEquals('new', $actual->getDescription());
+		$this->assertEquals('old', $actual->getDescriptionPrev());
+		$this->assertEquals('title', $actual->getTitle());
+		$this->assertEquals($duedate, $actual->getDuedate());
+		$this->assertEquals($startdate, $actual->getStartdate());
+		$this->assertEquals($done, $actual->getDone());
+	}
+
+	public function testUpdateDescriptionArchived() {
+		$card = new Card();
+		$card->setArchived(true);
+		$this->cardMapper->expects($this->once())->method('find')->willReturn($card);
+		$this->cardMapper->expects($this->never())->method('update');
+		$this->expectException(StatusException::class);
+		$this->cardService->updateDescription(123, 'new');
+	}
+
 	public static function dataReorder() {
 		return [
 			[0, 0, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]],