fix: enforce ephemeral retention on chat project membership changes

Project membership writes bypassed forced retention: assigning a chat to a
project, removing it, or deleting the project rewrote the conversation row
(chatProjectId) without setting isTemporary/expiredAt. On a deployment that
switched to ephemeral mode, touching an older permanent chat this way left it
visible and non-expiring.

Load the interface config on the assign and delete project routes and cascade
forced retention through the touched conversation(s): assign/remove caps the
single conversation, its messages, and its shares; delete caps every member
chat before unassigning. Extract the bucketed tag cascade into a shared helper
so the project cascade reuses the same conversion/backfill/cap logic, and add a
shared resolveForcedRetentionDate helper. All paths are a no-op outside forced
retention, so non-ephemeral behavior is unchanged.

packages/api/src/projects/handlers.ts

@@ -1,6 +1,7 @@
 import { isValidObjectIdString, logger } from '@librechat/data-schemas';
 
 import type {
+  AppConfig,
   ChatProjectMethods,
   ChatProjectSortBy,
   ChatProjectSortDirection,
@@ -23,6 +24,7 @@ interface ProjectUser {
 
 interface ProjectRequest extends Request {
   user?: ProjectUser;
+  config?: AppConfig;
 }
 
 type ProjectHandlerDependencies = Pick<
@@ -139,6 +141,7 @@ export function createProjectHandlers(deps: ProjectHandlerDependencies): {
         getUserId(req),
         conversationId,
         projectId,
+        req.config?.interfaceConfig,
       );
       if (!result) {
         return res.status(404).json({ error: CONVERSATION_NOT_FOUND });
@@ -208,7 +211,11 @@ export function createProjectHandlers(deps: ProjectHandlerDependencies): {
     }
 
     try {
-      const result = await deps.deleteChatProject(getUserId(req), projectId);
+      const result = await deps.deleteChatProject(
+        getUserId(req),
+        projectId,
+        req.config?.interfaceConfig,
+      );
       if (!result.deletedCount) {
         return res.status(404).json({ error: PROJECT_NOT_FOUND });
       }

packages/data-schemas/src/methods/chatProject.spec.ts

@@ -1,8 +1,15 @@
 import mongoose from 'mongoose';
+import { v4 as uuidv4 } from 'uuid';
+import { RetentionMode } from 'librechat-data-provider';
 import { MongoMemoryServer } from 'mongodb-memory-server';
-import { createModels } from '~/models';
-import type { IChatProject, IConversation } from '~/types';
+import type { IChatProject, IConversation, IMessage, ISharedLink } from '~/types';
 import { createChatProjectMethods, type ChatProjectMethods } from './chatProject';
+import { createModels } from '~/models';
+
+const ephemeralConfig = {
+  temporaryChatRetention: 24,
+  retentionMode: RetentionMode.EPHEMERAL,
+};
 
 jest.mock('~/config/winston', () => ({
   error: jest.fn(),
@@ -14,6 +21,8 @@ jest.mock('~/config/winston', () => ({
 let mongoServer: InstanceType<typeof MongoMemoryServer>;
 let ChatProject: mongoose.Model<IChatProject>;
 let Conversation: mongoose.Model<IConversation>;
+let Message: mongoose.Model<IMessage>;
+let SharedLink: mongoose.Model<ISharedLink>;
 let methods: ChatProjectMethods;
 let modelsToCleanup: string[] = [];
 
@@ -27,6 +36,8 @@ beforeAll(async () => {
 
   ChatProject = mongoose.models.ChatProject as mongoose.Model<IChatProject>;
   Conversation = mongoose.models.Conversation as mongoose.Model<IConversation>;
+  Message = mongoose.models.Message as mongoose.Model<IMessage>;
+  SharedLink = mongoose.models.SharedLink as mongoose.Model<ISharedLink>;
   methods = createChatProjectMethods(mongoose);
 
   await mongoose.connect(mongoUri);
@@ -46,6 +57,8 @@ afterAll(async () => {
 afterEach(async () => {
   await ChatProject.deleteMany({});
   await Conversation.deleteMany({});
+  await Message.deleteMany({});
+  await SharedLink.deleteMany({});
 });
 
 async function createConversation(user: string, conversationId: string, title: string) {
@@ -290,4 +303,95 @@ describe('ChatProject methods', () => {
     expect(assignment).toBeNull();
     expect(deleteResult.deletedCount).toBe(0);
   });
+
+  it('forces ephemeral retention on a permanent chat, its messages, and shares when assigning', async () => {
+    const project = await methods.createChatProject(user, { name: 'Ephemeral' });
+    await createConversation(user, 'convo-1', 'Permanent');
+    await Message.create([
+      { messageId: uuidv4(), conversationId: 'convo-1', user, text: 'first' },
+      { messageId: uuidv4(), conversationId: 'convo-1', user, text: 'second' },
+    ]);
+    await SharedLink.create({ conversationId: 'convo-1', user, shareId: uuidv4() });
+
+    await methods.assignConversationToProject(
+      user,
+      'convo-1',
+      project._id!.toString(),
+      ephemeralConfig,
+    );
+
+    const conversation = await Conversation.findOne({
+      user,
+      conversationId: 'convo-1',
+    }).lean<IConversation>();
+    expect(conversation?.isTemporary).toBe(true);
+    expect(conversation?.expiredAt).toBeInstanceOf(Date);
+
+    const messages = await Message.find({ user, conversationId: 'convo-1' }).lean<IMessage[]>();
+    expect(messages).toHaveLength(2);
+    for (const message of messages) {
+      expect(message.isTemporary).toBe(true);
+      expect(message.expiredAt).toBeInstanceOf(Date);
+    }
+
+    const share = await SharedLink.findOne({ user, conversationId: 'convo-1' }).lean<ISharedLink>();
+    expect(share?.expiredAt).toBeInstanceOf(Date);
+  });
+
+  it('forces ephemeral retention when removing a chat from its project', async () => {
+    const project = await methods.createChatProject(user, { name: 'Ephemeral' });
+    await createConversation(user, 'convo-1', 'Permanent');
+    await methods.assignConversationToProject(user, 'convo-1', project._id!.toString());
+
+    await methods.assignConversationToProject(user, 'convo-1', null, ephemeralConfig);
+
+    const conversation = await Conversation.findOne({
+      user,
+      conversationId: 'convo-1',
+    }).lean<IConversation>();
+    expect(conversation?.chatProjectId).toBeUndefined();
+    expect(conversation?.isTemporary).toBe(true);
+    expect(conversation?.expiredAt).toBeInstanceOf(Date);
+  });
+
+  it('leaves retention untouched when assigning outside ephemeral mode', async () => {
+    const project = await methods.createChatProject(user, { name: 'Standard' });
+    await createConversation(user, 'convo-1', 'Permanent');
+
+    await methods.assignConversationToProject(user, 'convo-1', project._id!.toString());
+
+    const conversation = await Conversation.findOne({
+      user,
+      conversationId: 'convo-1',
+    }).lean<IConversation>();
+    expect(conversation?.isTemporary ?? null).not.toBe(true);
+    expect(conversation?.expiredAt ?? null).toBeNull();
+  });
+
+  it('forces ephemeral retention on member chats when deleting a project', async () => {
+    const project = await methods.createChatProject(user, { name: 'Ephemeral' });
+    const projectId = project._id!.toString();
+    await createConversation(user, 'convo-1', 'First');
+    await createConversation(user, 'convo-2', 'Second');
+    await methods.assignConversationToProject(user, 'convo-1', projectId);
+    await methods.assignConversationToProject(user, 'convo-2', projectId);
+    await Message.create({ messageId: uuidv4(), conversationId: 'convo-1', user, text: 'hi' });
+
+    await methods.deleteChatProject(user, projectId, ephemeralConfig);
+
+    const conversations = await Conversation.find({
+      user,
+      conversationId: { $in: ['convo-1', 'convo-2'] },
+    }).lean<IConversation[]>();
+    expect(conversations).toHaveLength(2);
+    for (const conversation of conversations) {
+      expect(conversation.chatProjectId).toBeUndefined();
+      expect(conversation.isTemporary).toBe(true);
+      expect(conversation.expiredAt).toBeInstanceOf(Date);
+    }
+
+    const message = await Message.findOne({ user, conversationId: 'convo-1' }).lean<IMessage>();
+    expect(message?.isTemporary).toBe(true);
+    expect(message?.expiredAt).toBeInstanceOf(Date);
+  });
 });

packages/data-schemas/src/methods/chatProject.ts

@@ -1,9 +1,22 @@
+import { isForcedTemporaryRetention } from 'librechat-data-provider';
 import type { FilterQuery, Model, SortOrder, Types } from 'mongoose';
-import logger from '~/config/winston';
+import type {
+  AppConfig,
+  IChatProject,
+  IChatProjectDocument,
+  IConversation,
+  IMessage,
+  ISharedLink,
+} from '~/types';
+import {
+  buildRetentionVisibilityFilter,
+  cascadeForcedConversationRetention,
+  cascadeForcedRetentionByProject,
+  resolveForcedRetentionDate,
+} from '~/utils/retention';
 import { isValidObjectIdString } from '~/utils/objectId';
-import { buildRetentionVisibilityFilter } from '~/utils/retention';
 import { escapeRegExp } from '~/utils/string';
-import type { IChatProject, IChatProjectDocument, IConversation } from '~/types';
+import logger from '~/config/winston';
 
 export type ChatProjectSortBy = 'name' | 'createdAt' | 'lastConversationAt';
 export type ChatProjectSortDirection = 'asc' | 'desc';
@@ -51,11 +64,16 @@ export interface ChatProjectMethods {
     projectId: string,
     input: UpdateChatProjectInput,
   ): Promise<IChatProject | null>;
-  deleteChatProject(user: string, projectId: string): Promise<DeleteChatProjectResult>;
+  deleteChatProject(
+    user: string,
+    projectId: string,
+    interfaceConfig?: AppConfig['interfaceConfig'],
+  ): Promise<DeleteChatProjectResult>;
   assignConversationToProject(
     user: string,
     conversationId: string,
     projectId: string | null,
+    interfaceConfig?: AppConfig['interfaceConfig'],
   ): Promise<AssignConversationToProjectResult | null>;
   refreshChatProjectStats(user: string, projectId: string): Promise<IChatProject | null>;
 }
@@ -252,6 +270,54 @@ export async function updateChatProjectLastConversationForUser(
 }
 
 export function createChatProjectMethods(mongoose: typeof import('mongoose')): ChatProjectMethods {
+  /**
+   * Converts a project's conversations to the forced (ephemeral) window when the deployment runs
+   * in ephemeral mode. Assigning, removing, or bulk-unassigning a chat rewrites its row without
+   * setting `isTemporary`/`expiredAt`, so a permanent chat organized after the install switched
+   * to ephemeral would otherwise stay visible and never expire. A no-op outside forced retention.
+   */
+  function forceProjectConversationRetention(
+    user: string,
+    chatProjectId: string,
+    interfaceConfig?: AppConfig['interfaceConfig'],
+  ): Promise<void> {
+    if (!isForcedTemporaryRetention(interfaceConfig?.retentionMode)) {
+      return Promise.resolve();
+    }
+    const Conversation = mongoose.models.Conversation as Model<IConversation>;
+    const Message = mongoose.models.Message as Model<IMessage>;
+    const SharedLink = mongoose.models.SharedLink as Model<ISharedLink>;
+    return cascadeForcedRetentionByProject(
+      Conversation,
+      Message,
+      SharedLink,
+      user,
+      chatProjectId,
+      resolveForcedRetentionDate(interfaceConfig),
+    );
+  }
+
+  function forceConversationRetention(
+    user: string,
+    conversationId: string,
+    interfaceConfig?: AppConfig['interfaceConfig'],
+  ): Promise<void> {
+    if (!isForcedTemporaryRetention(interfaceConfig?.retentionMode)) {
+      return Promise.resolve();
+    }
+    const Conversation = mongoose.models.Conversation as Model<IConversation>;
+    const Message = mongoose.models.Message as Model<IMessage>;
+    const SharedLink = mongoose.models.SharedLink as Model<ISharedLink>;
+    return cascadeForcedConversationRetention(
+      Conversation,
+      Message,
+      SharedLink,
+      user,
+      conversationId,
+      resolveForcedRetentionDate(interfaceConfig),
+    );
+  }
+
   async function createChatProject(
     user: string,
     input: CreateChatProjectInput,
@@ -360,6 +426,7 @@ export function createChatProjectMethods(mongoose: typeof import('mongoose')): C
   async function deleteChatProject(
     user: string,
     projectId: string,
+    interfaceConfig?: AppConfig['interfaceConfig'],
   ): Promise<DeleteChatProjectResult> {
     if (!isValidObjectIdString(projectId)) {
       return { deletedCount: 0, modifiedCount: 0 };
@@ -373,6 +440,8 @@ export function createChatProjectMethods(mongoose: typeof import('mongoose')): C
       return { deletedCount: 0, modifiedCount: 0 };
     }
 
+    await forceProjectConversationRetention(user, projectId, interfaceConfig);
+
     const [conversationResult, deleteResult] = await Promise.all([
       Conversation.updateMany(
         { user, chatProjectId: projectId },
@@ -391,6 +460,7 @@ export function createChatProjectMethods(mongoose: typeof import('mongoose')): C
     user: string,
     conversationId: string,
     projectId: string | null,
+    interfaceConfig?: AppConfig['interfaceConfig'],
   ): Promise<AssignConversationToProjectResult | null> {
     const ChatProject = mongoose.models.ChatProject as Model<IChatProjectDocument>;
     const Conversation = mongoose.models.Conversation as Model<IConversation>;
@@ -430,6 +500,8 @@ export function createChatProjectMethods(mongoose: typeof import('mongoose')): C
       return null;
     }
 
+    await forceConversationRetention(user, conversationId, interfaceConfig);
+
     const projectIds = new Set(
       [previousProjectId, normalizedProjectId].filter((id): id is string => Boolean(id)),
     );

packages/data-schemas/src/utils/retention.ts

@@ -1,6 +1,7 @@
 import type { FilterQuery, Model } from 'mongoose';
-import type { IConversation, IMessage, ISharedLink } from '~/types';
-import { DEFAULT_RETENTION_HOURS } from './tempChatRetention';
+import type { AppConfig, IConversation, IMessage, ISharedLink } from '~/types';
+import { createTempChatExpirationDate, DEFAULT_RETENTION_HOURS } from './tempChatRetention';
+import logger from '~/config/winston';
 
 export type RetentionFilterDocument = {
   isTemporary?: boolean | null;
@@ -32,6 +33,21 @@ export const buildRetentionVisibilityFilter = <
 export const createFallbackRetentionDate = (now: number = Date.now()): Date =>
   new Date(now + DEFAULT_RETENTION_HOURS * 60 * 60 * 1000);
 
+/**
+ * Resolves the forced-retention deadline from the interface config, falling back to the default
+ * window when the configured retention hours cannot be computed.
+ */
+export const resolveForcedRetentionDate = (
+  interfaceConfig?: AppConfig['interfaceConfig'],
+): Date => {
+  try {
+    return createTempChatExpirationDate(interfaceConfig);
+  } catch (err) {
+    logger.error('Error creating forced retention expiration date:', err);
+    return createFallbackRetentionDate();
+  }
+};
+
 /**
  * Matches retention documents that do not yet conform to a forced (ephemeral) deadline:
  * not temporary, missing an expiration, or expiring later than the forced window. The
@@ -204,31 +220,32 @@ export const cascadeForcedConversationRetention = async (
 };
 
 /**
- * Bulk-applies forced retention to every conversation carrying a bookmark tag. A tag rename
- * or delete writes conversation rows directly (`Conversation.updateMany`) without setting
- * `isTemporary`/`expiredAt`, so a permanent chat tagged before the install switched to
- * ephemeral would otherwise stay visible and never expire. One pass converts the chats,
- * backfills their messages, and caps their shares; the gap filter keeps it a no-op for chats
- * that already conform and never extends a chat that already expires sooner.
+ * Bulk-applies forced retention to the user's conversations selected by `conversationMatch`
+ * (a bookmark tag, a chat project, etc.). Writes that touch these rows directly
+ * (`Conversation.updateMany`) without setting `isTemporary`/`expiredAt` would otherwise leave a
+ * permanent chat visible and non-expiring after an install switched to ephemeral. Chats are
+ * bucketed by their capped deadline so each bucket converts the chats, backfills their messages,
+ * and caps their shares in one pass; the gap filter keeps it a no-op for chats that already
+ * conform and never extends a chat that already expires sooner.
  */
-export const cascadeForcedRetentionByTag = async (
+const cascadeForcedRetentionForConversationSet = async (
   Conversation: Model<IConversation>,
   Message: Model<IMessage>,
   SharedLink: Model<ISharedLink>,
   userId: string,
-  tag: string,
+  conversationMatch: FilterQuery<IConversation>,
   forcedExpiredAt: Date,
 ): Promise<void> => {
-  const taggedConversations = await Conversation.find(
-    { user: userId, tags: tag },
+  const conversations = await Conversation.find(
+    { user: userId, ...conversationMatch } as FilterQuery<IConversation>,
     'conversationId isTemporary expiredAt',
   ).lean<Array<RetentionFilterDocument & { conversationId?: string }>>();
-  if (taggedConversations.length === 0) {
+  if (conversations.length === 0) {
     return;
   }
 
   const retentionBuckets = new Map<number, { expiredAt: Date; conversationIds: string[] }>();
-  for (const convo of taggedConversations) {
+  for (const convo of conversations) {
     if (typeof convo.conversationId !== 'string' || convo.conversationId.length === 0) {
       continue;
     }
@@ -278,6 +295,52 @@ export const cascadeForcedRetentionByTag = async (
   }
 };
 
+/**
+ * Bulk-applies forced retention to every conversation carrying a bookmark tag. A tag rename or
+ * delete writes conversation rows directly without setting `isTemporary`/`expiredAt`, so a
+ * permanent chat tagged before the install switched to ephemeral would otherwise stay visible
+ * and never expire.
+ */
+export const cascadeForcedRetentionByTag = (
+  Conversation: Model<IConversation>,
+  Message: Model<IMessage>,
+  SharedLink: Model<ISharedLink>,
+  userId: string,
+  tag: string,
+  forcedExpiredAt: Date,
+): Promise<void> =>
+  cascadeForcedRetentionForConversationSet(
+    Conversation,
+    Message,
+    SharedLink,
+    userId,
+    { tags: tag } as FilterQuery<IConversation>,
+    forcedExpiredAt,
+  );
+
+/**
+ * Bulk-applies forced retention to every conversation in a chat project. Assigning a chat to a
+ * project, removing it, or deleting the project rewrites conversation rows without setting
+ * `isTemporary`/`expiredAt`, so a permanent chat organized after the install switched to
+ * ephemeral would otherwise stay visible and never expire.
+ */
+export const cascadeForcedRetentionByProject = (
+  Conversation: Model<IConversation>,
+  Message: Model<IMessage>,
+  SharedLink: Model<ISharedLink>,
+  userId: string,
+  chatProjectId: string,
+  forcedExpiredAt: Date,
+): Promise<void> =>
+  cascadeForcedRetentionForConversationSet(
+    Conversation,
+    Message,
+    SharedLink,
+    userId,
+    { chatProjectId } as FilterQuery<IConversation>,
+    forcedExpiredAt,
+  );
+
 /**
  * One-time backfill of forced (ephemeral) retention over pre-existing data. Convert-on-touch
  * only converts conversations that are subsequently written, so enabling ephemeral mode on a