diff --git a/api/app/clients/tools/structured/DALLE3.js b/api/app/clients/tools/structured/DALLE3.js
index e78c0cba60..8ce46323af 100644
--- a/api/app/clients/tools/structured/DALLE3.js
+++ b/api/app/clients/tools/structured/DALLE3.js
@@ -48,6 +48,7 @@ class DALLE3 extends Tool {
     this.returnMetadata = fields.returnMetadata ?? false;
 
     this.userId = fields.userId;
+    this.tenantId = fields.req?.user?.tenantId;
     this.fileStrategy = fields.fileStrategy;
     /** @type {boolean} */
     this.isAgent = fields.isAgent;
@@ -228,6 +229,7 @@ Error Message: ${error.message}`);
         fileName: imageName,
         fileStrategy: this.fileStrategy,
         context: FileContext.image_generation,
+        tenantId: this.tenantId,
       });
 
       if (this.returnMetadata) {
diff --git a/api/app/clients/tools/structured/FluxAPI.js b/api/app/clients/tools/structured/FluxAPI.js
index 9fce38b86a..dc94a25e82 100644
--- a/api/app/clients/tools/structured/FluxAPI.js
+++ b/api/app/clients/tools/structured/FluxAPI.js
@@ -109,6 +109,7 @@ class FluxAPI extends Tool {
     this.override = fields.override ?? false;
 
     this.userId = fields.userId;
+    this.tenantId = fields.req?.user?.tenantId;
     this.fileStrategy = fields.fileStrategy;
 
     /** @type {boolean} **/
@@ -341,6 +342,7 @@ class FluxAPI extends Tool {
         fileName: imageName,
         basePath: 'images',
         context: FileContext.image_generation,
+        tenantId: this.tenantId,
       });
 
       logger.debug('[FluxAPI] Image saved to path:', result.filepath);
@@ -571,6 +573,7 @@ class FluxAPI extends Tool {
         fileName: imageName,
         basePath: 'images',
         context: FileContext.image_generation,
+        tenantId: this.tenantId,
       });
 
       logger.debug('[FluxAPI] Finetuned image saved to path:', result.filepath);
diff --git a/api/app/clients/tools/structured/specs/imageTools-agent.spec.js b/api/app/clients/tools/structured/specs/imageTools-agent.spec.js
index 50345f3504..f88b76a116 100644
--- a/api/app/clients/tools/structured/specs/imageTools-agent.spec.js
+++ b/api/app/clients/tools/structured/specs/imageTools-agent.spec.js
@@ -99,6 +99,14 @@ describe('image tools - agent mode ToolMessage format', () => {
       expect(dalle.responseFormat).not.toBe('content_and_artifact');
     });
 
+    it('keeps tenant context without retaining the request object', () => {
+      const req = { user: { tenantId: 'tenant-a' }, socket: {} };
+      const dalle = new DALLE3({ isAgent: false, processFileURL: jest.fn(), req });
+
+      expect(dalle.tenantId).toBe('tenant-a');
+      expect(dalle.req).toBeUndefined();
+    });
+
     it('invoke() returns ToolMessage with base64 in artifact, not serialized in content', async () => {
       const dalle = new DALLE3({ isAgent: true });
       const result = await dalle.invoke(
@@ -172,6 +180,14 @@ describe('image tools - agent mode ToolMessage format', () => {
       expect(flux.responseFormat).not.toBe('content_and_artifact');
     });
 
+    it('keeps tenant context without retaining the request object', () => {
+      const req = { user: { tenantId: 'tenant-a' }, socket: {} };
+      const flux = new FluxAPI({ isAgent: false, processFileURL: jest.fn(), req });
+
+      expect(flux.tenantId).toBe('tenant-a');
+      expect(flux.req).toBeUndefined();
+    });
+
     it('invoke() returns ToolMessage with base64 in artifact, not serialized in content', async () => {
       const flux = new FluxAPI({ isAgent: true });
       const invokePromise = flux.invoke(
diff --git a/api/server/controllers/AuthController.js b/api/server/controllers/AuthController.js
index d61bcc2844..5a4ce8a10a 100644
--- a/api/server/controllers/AuthController.js
+++ b/api/server/controllers/AuthController.js
@@ -120,7 +120,11 @@ const refreshController = async (req, res) => {
         );
       }
 
-      const token = setOpenIDAuthTokens(tokenset, req, res, user._id.toString(), refreshToken);
+      const token = setOpenIDAuthTokens(tokenset, req, res, {
+        userId: user._id.toString(),
+        existingRefreshToken: refreshToken,
+        tenantId: user.tenantId,
+      });
 
       const { password: _pw, __v: _v, totpSecret: _ts, backupCodes: _bc, ...safeUser } = user;
       return res.status(200).send({ token, user: safeUser });
@@ -146,7 +150,7 @@ const refreshController = async (req, res) => {
     const userId = payload.id;
 
     if (process.env.NODE_ENV === 'CI') {
-      const token = await setAuthTokens(userId, res);
+      const token = await setAuthTokens(userId, res, null, req);
       return res.status(200).send({ token, user });
     }
 
@@ -160,7 +164,7 @@ const refreshController = async (req, res) => {
     );
 
     if (session && session.expiration > new Date()) {
-      const token = await setAuthTokens(userId, res, session);
+      const token = await setAuthTokens(userId, res, session, req);
 
       res.status(200).send({ token, user });
     } else if (req?.query?.retry) {
diff --git a/api/server/controllers/agents/v1.js b/api/server/controllers/agents/v1.js
index 23c8341839..4f04a00be7 100644
--- a/api/server/controllers/agents/v1.js
+++ b/api/server/controllers/agents/v1.js
@@ -960,6 +960,7 @@ const uploadAgentAvatarHandler = async (req, res) => {
       userId: req.user.id,
       manual: 'false',
       agentId: agent_id,
+      tenantId: req.user.tenantId,
     });
 
     const image = {
@@ -972,7 +973,11 @@ const uploadAgentAvatarHandler = async (req, res) => {
     if (_avatar && _avatar.source) {
       const { deleteFile } = getStrategyFunctions(_avatar.source);
       try {
-        await deleteFile(req, { filepath: _avatar.filepath });
+        await deleteFile(req, {
+          filepath: _avatar.filepath,
+          user: req.user.id,
+          tenantId: req.user.tenantId,
+        });
         await db.deleteFileByFilter({ user: req.user.id, filepath: _avatar.filepath });
       } catch (error) {
         logger.error('[/:agent_id/avatar] Error deleting old avatar', error);
diff --git a/api/server/controllers/assistants/v1.js b/api/server/controllers/assistants/v1.js
index c441b7ec59..19be145795 100644
--- a/api/server/controllers/assistants/v1.js
+++ b/api/server/controllers/assistants/v1.js
@@ -328,7 +328,11 @@ const uploadAssistantAvatar = async (req, res) => {
     if (_metadata.avatar && _metadata.avatar_source) {
       const { deleteFile } = getStrategyFunctions(_metadata.avatar_source);
       try {
-        await deleteFile(req, { filepath: _metadata.avatar });
+        await deleteFile(req, {
+          filepath: _metadata.avatar,
+          user: req.user.id,
+          tenantId: req.user.tenantId,
+        });
         await deleteFileByFilter({ user: req.user.id, filepath: _metadata.avatar });
       } catch (error) {
         logger.error('[/:assistant_id/avatar] Error deleting old avatar', error);
diff --git a/api/server/controllers/auth/LoginController.js b/api/server/controllers/auth/LoginController.js
index 930eee86be..bf606b1dea 100644
--- a/api/server/controllers/auth/LoginController.js
+++ b/api/server/controllers/auth/LoginController.js
@@ -16,7 +16,7 @@ const loginController = async (req, res) => {
     const { password: _p, totpSecret: _t, __v, ...user } = req.user;
     user.id = user._id.toString();
 
-    const token = await setAuthTokens(req.user._id, res);
+    const token = await setAuthTokens(req.user._id, res, null, req);
 
     return res.status(200).send({ token, user });
   } catch (err) {
diff --git a/api/server/controllers/auth/LogoutController.js b/api/server/controllers/auth/LogoutController.js
index ae1c94a7c9..95e6c8965c 100644
--- a/api/server/controllers/auth/LogoutController.js
+++ b/api/server/controllers/auth/LogoutController.js
@@ -44,7 +44,10 @@ const logoutController = async (req, res) => {
     res.clearCookie('openid_id_token');
     res.clearCookie('openid_user_id');
     res.clearCookie('token_provider');
-    clearCloudFrontCookies(res);
+    clearCloudFrontCookies(res, {
+      userId: req.user?.id ?? req.user?._id?.toString?.(),
+      tenantId: req.user?.tenantId,
+    });
     const response = { message };
     if (
       isOpenIdUser &&
diff --git a/api/server/controllers/auth/LogoutController.spec.js b/api/server/controllers/auth/LogoutController.spec.js
index ff02f5237e..e6c3149217 100644
--- a/api/server/controllers/auth/LogoutController.spec.js
+++ b/api/server/controllers/auth/LogoutController.spec.js
@@ -261,12 +261,15 @@ describe('LogoutController', () => {
     });
 
     it('calls clearCloudFrontCookies on successful logout', async () => {
-      const req = buildReq();
+      const req = buildReq({ user: { _id: 'user1', tenantId: 'tenantA' } });
       const res = buildRes();
 
       await logoutController(req, res);
 
-      expect(mockClearCloudFrontCookies).toHaveBeenCalledWith(res);
+      expect(mockClearCloudFrontCookies).toHaveBeenCalledWith(res, {
+        userId: 'user1',
+        tenantId: 'tenantA',
+      });
     });
   });
 
diff --git a/api/server/controllers/auth/TwoFactorAuthController.js b/api/server/controllers/auth/TwoFactorAuthController.js
index 9e4af2e986..23cdd8b078 100644
--- a/api/server/controllers/auth/TwoFactorAuthController.js
+++ b/api/server/controllers/auth/TwoFactorAuthController.js
@@ -50,7 +50,7 @@ const verify2FAWithTempToken = async (req, res) => {
     delete userData.backupCodes;
     userData.id = user._id.toString();
 
-    const authToken = await setAuthTokens(user._id, res);
+    const authToken = await setAuthTokens(user._id, res, null, req);
     return res.status(200).json({ token: authToken, user: userData });
   } catch (err) {
     logger.error('[verify2FAWithTempToken]', err);
diff --git a/api/server/controllers/auth/oauth.js b/api/server/controllers/auth/oauth.js
index 917e9e2bef..31499f7de6 100644
--- a/api/server/controllers/auth/oauth.js
+++ b/api/server/controllers/auth/oauth.js
@@ -68,9 +68,12 @@ function createOAuthHandler(redirectUri = domains.client) {
         isEnabled(process.env.OPENID_REUSE_TOKENS) === true
       ) {
         await syncUserEntraGroupMemberships(req.user, req.user.tokenset.access_token);
-        setOpenIDAuthTokens(req.user.tokenset, req, res, req.user._id.toString());
+        setOpenIDAuthTokens(req.user.tokenset, req, res, {
+          userId: req.user._id.toString(),
+          tenantId: req.user.tenantId,
+        });
       } else {
-        await setAuthTokens(req.user._id, res);
+        await setAuthTokens(req.user._id, res, null, req);
       }
       res.redirect(redirectUri);
     } catch (err) {
diff --git a/api/server/middleware/accessResources/fileAccess.js b/api/server/middleware/accessResources/fileAccess.js
index 0f77a61175..230148fb53 100644
--- a/api/server/middleware/accessResources/fileAccess.js
+++ b/api/server/middleware/accessResources/fileAccess.js
@@ -60,6 +60,14 @@ const checkAgentBasedFileAccess = async ({ userId, role, fileId }) => {
   }
 };
 
+const getTenantId = (value) => value?.toString?.() ?? null;
+
+const denyFileAccess = (res) =>
+  res.status(403).json({
+    error: 'Forbidden',
+    message: 'Insufficient permissions to access this file',
+  });
+
 /**
  * Middleware to check if user can access a file
  * Checks: 1) File ownership, 2) Agent-based access (file inherits agent permissions)
@@ -91,6 +99,15 @@ const fileAccess = async (req, res, next) => {
       });
     }
 
+    const fileTenantId = getTenantId(file.tenantId);
+    const userTenantId = getTenantId(req.user?.tenantId);
+    // Tenant-scoped files are restricted to their tenant. Legacy files without
+    // tenantId remain governed by owner/agent ACLs for non-tenant migrations.
+    if (fileTenantId && fileTenantId !== userTenantId) {
+      logger.warn(`[fileAccess] User ${userId} denied cross-tenant access to file ${fileId}`);
+      return denyFileAccess(res);
+    }
+
     if (file.user && file.user.toString() === userId) {
       req.fileAccess = { file };
       return next();
@@ -104,10 +121,7 @@ const fileAccess = async (req, res, next) => {
     }
 
     logger.warn(`[fileAccess] User ${userId} denied access to file ${fileId}`);
-    return res.status(403).json({
-      error: 'Forbidden',
-      message: 'Insufficient permissions to access this file',
-    });
+    return denyFileAccess(res);
   } catch (error) {
     logger.error('[fileAccess] Error checking file access:', error);
     return res.status(500).json({
diff --git a/api/server/middleware/accessResources/fileAccess.spec.js b/api/server/middleware/accessResources/fileAccess.spec.js
index 72896b0629..90b7d8dca7 100644
--- a/api/server/middleware/accessResources/fileAccess.spec.js
+++ b/api/server/middleware/accessResources/fileAccess.spec.js
@@ -1,4 +1,5 @@
 const mongoose = require('mongoose');
+const { tenantStorage } = require('@librechat/data-schemas');
 const { ResourceType, PrincipalType, PrincipalModel } = require('librechat-data-provider');
 const { MongoMemoryServer } = require('mongodb-memory-server');
 const { fileAccess } = require('./fileAccess');
@@ -115,6 +116,50 @@ describe('fileAccess middleware', () => {
       });
     });
 
+    test('should deny access when tenant does not match even if user owns the file', async () => {
+      await tenantStorage.run({ tenantId: 'tenant-a' }, async () =>
+        createFile({
+          user: testUser._id.toString(),
+          file_id: 'file_owned_by_user_other_tenant',
+          filepath: '/test/file.txt',
+          filename: 'file.txt',
+          type: 'text/plain',
+          size: 100,
+          tenantId: 'tenant-a',
+        }),
+      );
+
+      req.user.tenantId = 'tenant-b';
+      req.params.file_id = 'file_owned_by_user_other_tenant';
+      await fileAccess(req, res, next);
+
+      expect(next).not.toHaveBeenCalled();
+      expect(res.status).toHaveBeenCalledWith(403);
+      expect(res.json).toHaveBeenCalledWith({
+        error: 'Forbidden',
+        message: 'Insufficient permissions to access this file',
+      });
+    });
+
+    test('should allow tenant-scoped users to access owned legacy files without tenantId', async () => {
+      await createFile({
+        user: testUser._id.toString(),
+        file_id: 'legacy_file_owned_by_user',
+        filepath: '/test/legacy.txt',
+        filename: 'legacy.txt',
+        type: 'text/plain',
+        size: 100,
+      });
+
+      req.user.tenantId = 'tenant-b';
+      req.params.file_id = 'legacy_file_owned_by_user';
+      await fileAccess(req, res, next);
+
+      expect(next).toHaveBeenCalled();
+      expect(req.fileAccess.file.file_id).toBe('legacy_file_owned_by_user');
+      expect(res.status).not.toHaveBeenCalled();
+    });
+
     test('should return 404 when file does not exist', async () => {
       req.params.file_id = 'non_existent_file';
       await fileAccess(req, res, next);
@@ -223,6 +268,50 @@ describe('fileAccess middleware', () => {
       expect(req.fileAccess).toBeDefined();
     });
 
+    test('should deny cross-tenant access even when user has VIEW permission on agent with file', async () => {
+      await tenantStorage.run({ tenantId: 'tenant-a' }, async () =>
+        createFile({
+          user: otherUser._id.toString(),
+          file_id: 'cross_tenant_shared_file',
+          filepath: '/test/cross-tenant.txt',
+          filename: 'cross-tenant.txt',
+          type: 'text/plain',
+          size: 100,
+          tenantId: 'tenant-a',
+        }),
+      );
+
+      const agent = await createAgent({
+        id: `agent_cross_tenant_${Date.now()}`,
+        name: 'Cross Tenant Agent',
+        provider: 'openai',
+        model: 'gpt-4',
+        author: otherUser._id,
+        tool_resources: {
+          execute_code: {
+            file_ids: ['cross_tenant_shared_file'],
+          },
+        },
+      });
+
+      await AclEntry.create({
+        principalType: PrincipalType.USER,
+        principalId: testUser._id,
+        principalModel: PrincipalModel.USER,
+        resourceType: ResourceType.AGENT,
+        resourceId: agent._id,
+        permBits: 1,
+        grantedBy: otherUser._id,
+      });
+
+      req.user.tenantId = 'tenant-b';
+      req.params.file_id = 'cross_tenant_shared_file';
+      await fileAccess(req, res, next);
+
+      expect(next).not.toHaveBeenCalled();
+      expect(res.status).toHaveBeenCalledWith(403);
+    });
+
     test('should check file in ocr tool_resources', async () => {
       await createAgent({
         id: `agent_ocr_${Date.now()}`,
diff --git a/api/server/routes/files/avatar.js b/api/server/routes/files/avatar.js
index f5c9379178..db00674f82 100644
--- a/api/server/routes/files/avatar.js
+++ b/api/server/routes/files/avatar.js
@@ -29,7 +29,12 @@ router.post('/', async (req, res) => {
     });
 
     const { processAvatar } = getStrategyFunctions(fileStrategy);
-    const url = await processAvatar({ buffer: resizedBuffer, userId, manual });
+    const url = await processAvatar({
+      buffer: resizedBuffer,
+      userId,
+      manual,
+      tenantId: req.user.tenantId,
+    });
 
     res.json({ url });
   } catch (error) {
diff --git a/api/server/routes/files/files.js b/api/server/routes/files/files.js
index 0e3273efe2..8183bca973 100644
--- a/api/server/routes/files/files.js
+++ b/api/server/routes/files/files.js
@@ -29,7 +29,7 @@ const { getOpenAIClient } = require('~/server/controllers/assistants/helpers');
 const { hasCapability } = require('~/server/middleware/roles/capabilities');
 const { checkPermission } = require('~/server/services/PermissionService');
 const { hasAccessToFilesViaAgent } = require('~/server/services/Files');
-const { getContentDisposition } = require('~/server/utils/files');
+const { cleanFileName, getContentDisposition } = require('~/server/utils/files');
 const { getLogStores } = require('~/cache');
 const { Readable } = require('stream');
 const db = require('~/models');
@@ -164,7 +164,7 @@ router.delete('/', async (req, res) => {
       }
     }
 
-    if (nonOwnedFiles.length === 0) {
+    if (dbFiles.length > 0 && nonOwnedFiles.length === 0) {
       await processDeleteRequest({ req, files: ownedFiles });
       logger.debug(
         `[/files] Files deleted successfully: ${ownedFiles
@@ -214,9 +214,28 @@ router.delete('/', async (req, res) => {
       });
 
       const toolResourceFiles = agent.tool_resources?.[req.body.tool_resource]?.file_ids ?? [];
-      const agentFiles = files.filter((f) => toolResourceFiles.includes(f.file_id));
+      const agentFiles = files
+        .filter((f) => toolResourceFiles.includes(f.file_id))
+        .map((file) => ({ tool_resource: req.body.tool_resource, file_id: file.file_id }));
+      const accessMap = await hasAccessToFilesViaAgent({
+        userId: req.user.id,
+        role: req.user.role,
+        fileIds: agentFiles.map((file) => file.file_id),
+        agentId: req.body.agent_id,
+        isDelete: true,
+      });
+      const unauthorizedFiles = agentFiles.filter((file) => !accessMap.get(file.file_id));
+      if (unauthorizedFiles.length > 0) {
+        return res.status(403).json({
+          message: 'You can only delete files you have access to',
+          unauthorizedFiles: unauthorizedFiles.map((file) => file.file_id),
+        });
+      }
 
-      await processDeleteRequest({ req, files: agentFiles });
+      await db.removeAgentResourceFiles({
+        agent_id: req.body.agent_id,
+        files: agentFiles,
+      });
       res.status(200).json({ message: 'File associations removed successfully from agent' });
       return;
     }
@@ -375,6 +394,104 @@ router.get('/:file_id/preview', fileAccess, async (req, res) => {
   }
 });
 
+/**
+ * Returns a strategy-managed signed URL for an already-authorized file record.
+ */
+const getDirectDownloadURL = async ({
+  req,
+  file,
+  customFilename = cleanFileName(file.filename),
+}) => {
+  const { getDownloadURL } = getStrategyFunctions(file.source);
+  if (!getDownloadURL) {
+    return null;
+  }
+
+  return getDownloadURL({
+    req,
+    file,
+    customFilename,
+    contentType: file.type || 'application/octet-stream',
+  });
+};
+
+// Security allowlist: excludes internal ids, owner/tenant identifiers, and extracted text.
+// `filepath` stays included because cached TFile records need it for previews/deletes.
+const DOWNLOAD_METADATA_FIELDS = [
+  'conversationId',
+  'message',
+  'file_id',
+  'temp_file_id',
+  'bytes',
+  'model',
+  'embedded',
+  'filename',
+  'filepath',
+  'object',
+  'type',
+  'usage',
+  'context',
+  'source',
+  'filterSource',
+  'width',
+  'height',
+  'expiresAt',
+  'preview',
+  'textFormat',
+  'status',
+  'previewError',
+  'createdAt',
+  'updatedAt',
+];
+
+const getDownloadFileMetadata = (file) => {
+  const rawFile = typeof file.toObject === 'function' ? file.toObject() : file;
+  return DOWNLOAD_METADATA_FIELDS.reduce((metadata, field) => {
+    if (rawFile[field] !== undefined) {
+      metadata[field] = rawFile[field];
+    }
+    return metadata;
+  }, {});
+};
+
+router.get('/download-url/:userId/:file_id', fileAccess, async (req, res) => {
+  try {
+    const { userId, file_id } = req.params;
+    logger.debug(`File download URL requested by user ${userId}: ${file_id}`);
+
+    const file = req.fileAccess.file;
+    if (checkOpenAIStorage(file.source) && !file.model) {
+      logger.warn(
+        `File download URL requested by user ${userId} has no associated model: ${file_id}`,
+      );
+      return res.status(400).send('The model used when creating this file is not available');
+    }
+
+    const filename = cleanFileName(file.filename);
+    const downloadURL = checkOpenAIStorage(file.source)
+      ? null
+      : await getDirectDownloadURL({ req, file, customFilename: filename });
+
+    if (!downloadURL) {
+      logger.debug(
+        `File download URL requested by user ${userId} is not supported for source: ${file.source}`,
+      );
+      return res.status(501).send('Not Implemented');
+    }
+
+    res.setHeader('Cache-Control', 'no-store');
+    return res.status(200).json({
+      url: downloadURL,
+      filename,
+      type: file.type || 'application/octet-stream',
+      metadata: getDownloadFileMetadata(file),
+    });
+  } catch (error) {
+    logger.error('[DOWNLOAD URL ROUTE] Error generating file download URL:', error);
+    res.status(500).send('Error generating file download URL');
+  }
+});
+
 router.get('/download/:userId/:file_id', fileAccess, async (req, res) => {
   try {
     const { userId, file_id } = req.params;
@@ -388,10 +505,10 @@ router.get('/download/:userId/:file_id', fileAccess, async (req, res) => {
       return res.status(400).send('The model used when creating this file is not available');
     }
 
-    const { getDownloadStream } = getStrategyFunctions(file.source);
-    if (!getDownloadStream) {
+    const { getDownloadStream, getDownloadURL } = getStrategyFunctions(file.source);
+    if (!getDownloadStream && !getDownloadURL) {
       logger.warn(
-        `File download requested by user ${userId} has no stream method implemented: ${file.source}`,
+        `File download requested by user ${userId} has no download method implemented: ${file.source}`,
       );
       return res.status(501).send('Not Implemented');
     }
@@ -399,7 +516,7 @@ router.get('/download/:userId/:file_id', fileAccess, async (req, res) => {
     const setHeaders = () => {
       res.setHeader('Content-Disposition', getContentDisposition(file.filename));
       res.setHeader('Content-Type', 'application/octet-stream');
-      res.setHeader('X-File-Metadata', JSON.stringify(file));
+      res.setHeader('X-File-Metadata', JSON.stringify(getDownloadFileMetadata(file)));
     };
 
     if (checkOpenAIStorage(file.source)) {
@@ -426,6 +543,28 @@ router.get('/download/:userId/:file_id', fileAccess, async (req, res) => {
 
       stream.pipe(res);
     } else {
+      if (getDownloadURL && req.query.direct === 'true') {
+        try {
+          const downloadURL = await getDirectDownloadURL({ req, file });
+          if (downloadURL) {
+            res.setHeader('Cache-Control', 'no-store');
+            return res.redirect(302, downloadURL);
+          }
+        } catch (error) {
+          logger.warn(
+            '[DOWNLOAD ROUTE] Falling back to stream after URL generation failed:',
+            error,
+          );
+        }
+      }
+
+      if (!getDownloadStream) {
+        logger.warn(
+          `File download requested by user ${userId} has no stream method implemented: ${file.source}`,
+        );
+        return res.status(501).send('Not Implemented');
+      }
+
       const fileStream = await getDownloadStream(req, file.filepath);
 
       fileStream.on('error', (streamError) => {
diff --git a/api/server/routes/files/files.test.js b/api/server/routes/files/files.test.js
index 37cbf68b93..ac1167c09e 100644
--- a/api/server/routes/files/files.test.js
+++ b/api/server/routes/files/files.test.js
@@ -1,14 +1,16 @@
 const express = require('express');
 const request = require('supertest');
 const mongoose = require('mongoose');
+const { Readable } = require('stream');
 const { v4: uuidv4 } = require('uuid');
-const { createMethods } = require('@librechat/data-schemas');
+const { createMethods, tenantStorage } = require('@librechat/data-schemas');
 const { MongoMemoryServer } = require('mongodb-memory-server');
 const {
   SystemRoles,
   ResourceType,
   AccessRoleIds,
   PrincipalType,
+  FileSources,
 } = require('librechat-data-provider');
 const { createAgent, createFile } = require('~/models');
 
@@ -61,6 +63,7 @@ jest.mock('~/config', () => ({
 }));
 
 const { processDeleteRequest } = require('~/server/services/Files/process');
+const { getStrategyFunctions } = require('~/server/services/Files/strategies');
 
 // Import the router after mocks
 const router = require('./files');
@@ -110,10 +113,10 @@ describe('File Routes - Delete with Agent Access', () => {
 
     app.use((req, res, next) => {
       req.user = {
-        id: otherUserId || 'default-user',
+        id: otherUserId?.toString() || 'default-user',
         role: SystemRoles.USER,
       };
-      req.app = { locals: {} };
+      req.app.locals = {};
       next();
     });
 
@@ -430,5 +433,311 @@ describe('File Routes - Delete with Agent Access', () => {
       expect(response.body.unauthorizedFiles).toContain(fileId);
       expect(processDeleteRequest).not.toHaveBeenCalled();
     });
+
+    it('unlinks missing agent resource files without invoking storage deletion', async () => {
+      const missingFileId = uuidv4();
+      const agent = await createAgent({
+        id: uuidv4(),
+        name: 'Test Agent',
+        provider: 'openai',
+        model: 'gpt-4',
+        author: otherUserId,
+        tool_resources: {
+          file_search: {
+            file_ids: [missingFileId],
+          },
+        },
+      });
+
+      const response = await request(app)
+        .delete('/files')
+        .send({
+          agent_id: agent.id,
+          tool_resource: 'file_search',
+          files: [{ file_id: missingFileId, filepath: '/uploads/missing.txt' }],
+        });
+
+      expect(response.status).toBe(200);
+      expect(response.body.message).toBe('File associations removed successfully from agent');
+      expect(processDeleteRequest).not.toHaveBeenCalled();
+
+      const updatedAgent = await Agent.findOne({ id: agent.id }).lean();
+      expect(updatedAgent.tool_resources.file_search.file_ids).toEqual([]);
+    });
+
+    it('prevents unlinking missing agent resource files without agent edit access', async () => {
+      const missingFileId = uuidv4();
+      const agent = await createAgent({
+        id: uuidv4(),
+        name: 'Test Agent',
+        provider: 'openai',
+        model: 'gpt-4',
+        author: authorId,
+        tool_resources: {
+          file_search: {
+            file_ids: [missingFileId],
+          },
+        },
+      });
+
+      const response = await request(app)
+        .delete('/files')
+        .send({
+          agent_id: agent.id,
+          tool_resource: 'file_search',
+          files: [{ file_id: missingFileId, filepath: '/uploads/missing.txt' }],
+        });
+
+      expect(response.status).toBe(403);
+      expect(response.body.message).toBe('You can only delete files you have access to');
+      expect(response.body.unauthorizedFiles).toContain(missingFileId);
+      expect(processDeleteRequest).not.toHaveBeenCalled();
+
+      const updatedAgent = await Agent.findOne({ id: agent.id }).lean();
+      expect(updatedAgent.tool_resources.file_search.file_ids).toEqual([missingFileId]);
+    });
+  });
+
+  describe('GET /files/download-url/:userId/:file_id', () => {
+    it('returns a direct signed download URL when the strategy supports it', async () => {
+      const userFileId = uuidv4();
+      const getDownloadURL = jest.fn().mockResolvedValue('https://cdn.example.com/file.pdf?signed');
+      getStrategyFunctions.mockReturnValue({ getDownloadURL });
+
+      await createFile({
+        user: otherUserId,
+        file_id: userFileId,
+        filename: 'file.pdf',
+        filepath: 'uploads/user/file.pdf',
+        bytes: 200,
+        type: 'application/pdf',
+        source: FileSources.s3,
+        text: 'private extracted text',
+      });
+
+      const response = await request(app).get(`/files/download-url/${otherUserId}/${userFileId}`);
+
+      expect(response.status).toBe(200);
+      expect(response.body).toMatchObject({
+        url: 'https://cdn.example.com/file.pdf?signed',
+        filename: 'file.pdf',
+        type: 'application/pdf',
+      });
+      expect(response.headers['cache-control']).toBe('no-store');
+      expect(response.body.metadata).toMatchObject({
+        file_id: userFileId,
+        filename: 'file.pdf',
+        filepath: 'uploads/user/file.pdf',
+        source: FileSources.s3,
+      });
+      expect(response.body.metadata).not.toHaveProperty('_id');
+      expect(response.body.metadata).not.toHaveProperty('__v');
+      expect(response.body.metadata).not.toHaveProperty('user');
+      expect(response.body.metadata).not.toHaveProperty('tenantId');
+      expect(response.body.metadata).not.toHaveProperty('text');
+      expect(getDownloadURL).toHaveBeenCalledWith(
+        expect.objectContaining({
+          file: expect.objectContaining({ file_id: userFileId }),
+          customFilename: 'file.pdf',
+          contentType: 'application/pdf',
+        }),
+      );
+    });
+
+    it('returns 501 when the strategy does not support direct URLs', async () => {
+      const userFileId = uuidv4();
+      getStrategyFunctions.mockReturnValue({});
+
+      await createFile({
+        user: otherUserId,
+        file_id: userFileId,
+        filename: 'file.txt',
+        filepath: 'uploads/user/file.txt',
+        bytes: 200,
+        type: 'text/plain',
+        source: FileSources.local,
+      });
+
+      const response = await request(app).get(`/files/download-url/${otherUserId}/${userFileId}`);
+
+      expect(response.status).toBe(501);
+    });
+
+    it('denies tenant-scoped files before issuing a signed URL', async () => {
+      const userFileId = uuidv4();
+      const getDownloadURL = jest.fn().mockResolvedValue('https://cdn.example.com/file.pdf?signed');
+      getStrategyFunctions.mockReturnValue({ getDownloadURL });
+
+      await tenantStorage.run({ tenantId: 'tenant-a' }, async () =>
+        createFile({
+          user: otherUserId,
+          file_id: userFileId,
+          filename: 'file.pdf',
+          filepath: 'uploads/user/file.pdf',
+          bytes: 200,
+          type: 'application/pdf',
+          source: FileSources.s3,
+          tenantId: 'tenant-a',
+        }),
+      );
+
+      const response = await request(app).get(`/files/download-url/${otherUserId}/${userFileId}`);
+
+      expect(response.status).toBe(403);
+      expect(getDownloadURL).not.toHaveBeenCalled();
+    });
+
+    it('returns 500 when direct URL generation fails', async () => {
+      const userFileId = uuidv4();
+      const getDownloadURL = jest.fn().mockRejectedValue(new Error('signing failed'));
+      getStrategyFunctions.mockReturnValue({ getDownloadURL });
+
+      await createFile({
+        user: otherUserId,
+        file_id: userFileId,
+        filename: 'file.pdf',
+        filepath: 'uploads/user/file.pdf',
+        bytes: 200,
+        type: 'application/pdf',
+        source: FileSources.s3,
+      });
+
+      const response = await request(app).get(`/files/download-url/${otherUserId}/${userFileId}`);
+
+      expect(response.status).toBe(500);
+      expect(response.text).toBe('Error generating file download URL');
+    });
+  });
+
+  describe('GET /files/download/:userId/:file_id', () => {
+    it('streams proxied downloads by default when a direct URL is available', async () => {
+      const userFileId = uuidv4();
+      const getDownloadURL = jest.fn().mockResolvedValue('https://cdn.example.com/file.pdf?signed');
+      const getDownloadStream = jest.fn().mockResolvedValue(Readable.from(['file content']));
+      getStrategyFunctions.mockReturnValue({ getDownloadURL, getDownloadStream });
+
+      await createFile({
+        user: otherUserId,
+        file_id: userFileId,
+        filename: 'file.pdf',
+        filepath: 'uploads/user/file.pdf',
+        bytes: 200,
+        type: 'application/pdf',
+        source: FileSources.cloudfront,
+        text: 'private extracted text',
+      });
+
+      const response = await request(app).get(`/files/download/${otherUserId}/${userFileId}`);
+
+      expect(response.status).toBe(200);
+      expect(response.body.toString()).toBe('file content');
+      expect(response.headers.location).toBeUndefined();
+      const metadata = JSON.parse(response.headers['x-file-metadata']);
+      expect(metadata).toMatchObject({
+        file_id: userFileId,
+        filename: 'file.pdf',
+        filepath: 'uploads/user/file.pdf',
+        source: FileSources.cloudfront,
+      });
+      expect(metadata).not.toHaveProperty('_id');
+      expect(metadata).not.toHaveProperty('__v');
+      expect(metadata).not.toHaveProperty('user');
+      expect(metadata).not.toHaveProperty('tenantId');
+      expect(metadata).not.toHaveProperty('text');
+      expect(getDownloadURL).not.toHaveBeenCalled();
+      expect(getDownloadStream).toHaveBeenCalledWith(expect.any(Object), 'uploads/user/file.pdf');
+    });
+
+    it('redirects to a direct signed download URL when explicitly requested', async () => {
+      const userFileId = uuidv4();
+      const getDownloadURL = jest.fn().mockResolvedValue('https://cdn.example.com/file.pdf?signed');
+      const getDownloadStream = jest.fn();
+      getStrategyFunctions.mockReturnValue({ getDownloadURL, getDownloadStream });
+
+      await createFile({
+        user: otherUserId,
+        file_id: userFileId,
+        filename: 'file.pdf',
+        filepath: 'uploads/user/file.pdf',
+        bytes: 200,
+        type: 'application/pdf',
+        source: FileSources.cloudfront,
+      });
+
+      const response = await request(app).get(
+        `/files/download/${otherUserId}/${userFileId}?direct=true`,
+      );
+
+      expect(response.status).toBe(302);
+      expect(response.headers.location).toBe('https://cdn.example.com/file.pdf?signed');
+      expect(response.headers['x-file-metadata']).toBeUndefined();
+      expect(response.headers['cache-control']).toBe('no-store');
+      expect(getDownloadStream).not.toHaveBeenCalled();
+    });
+
+    it('falls back to streaming when direct URL generation fails', async () => {
+      const userFileId = uuidv4();
+      const getDownloadURL = jest.fn().mockRejectedValue(new Error('missing signing keys'));
+      const getDownloadStream = jest.fn().mockResolvedValue(Readable.from(['file content']));
+      getStrategyFunctions.mockReturnValue({ getDownloadURL, getDownloadStream });
+
+      await createFile({
+        user: otherUserId,
+        file_id: userFileId,
+        filename: 'file.txt',
+        filepath: 'uploads/user/file.txt',
+        bytes: 200,
+        type: 'text/plain',
+        source: FileSources.s3,
+      });
+
+      const response = await request(app).get(
+        `/files/download/${otherUserId}/${userFileId}?direct=true`,
+      );
+
+      expect(response.status).toBe(200);
+      expect(response.body.toString()).toBe('file content');
+      expect(response.headers.location).toBeUndefined();
+      expect(response.headers['cache-control']).toBeUndefined();
+      expect(getDownloadURL).toHaveBeenCalledWith(
+        expect.objectContaining({
+          file: expect.objectContaining({ file_id: userFileId }),
+          customFilename: 'file.txt',
+          contentType: 'text/plain',
+        }),
+      );
+      expect(getDownloadStream).toHaveBeenCalledWith(expect.any(Object), 'uploads/user/file.txt');
+    });
+
+    it('returns 501 when direct URL generation fails and no stream fallback exists', async () => {
+      const userFileId = uuidv4();
+      const getDownloadURL = jest.fn().mockRejectedValue(new Error('missing signing keys'));
+      getStrategyFunctions.mockReturnValue({ getDownloadURL });
+
+      await createFile({
+        user: otherUserId,
+        file_id: userFileId,
+        filename: 'file.txt',
+        filepath: 'uploads/user/file.txt',
+        bytes: 200,
+        type: 'text/plain',
+        source: FileSources.cloudfront,
+      });
+
+      const response = await request(app).get(
+        `/files/download/${otherUserId}/${userFileId}?direct=true`,
+      );
+
+      expect(response.status).toBe(501);
+      expect(response.text).toBe('Not Implemented');
+      expect(response.headers.location).toBeUndefined();
+      expect(getDownloadURL).toHaveBeenCalledWith(
+        expect.objectContaining({
+          file: expect.objectContaining({ file_id: userFileId }),
+          customFilename: 'file.txt',
+          contentType: 'text/plain',
+        }),
+      );
+    });
   });
 });
diff --git a/api/server/routes/skills.js b/api/server/routes/skills.js
index 9e9676fb45..84a303d145 100644
--- a/api/server/routes/skills.js
+++ b/api/server/routes/skills.js
@@ -138,10 +138,12 @@ const importHandler = createImportHandler({
   upsertSkillFile,
   saveBuffer: (req, { userId, buffer, fileName, basePath, isImage }) => {
     const storage = resolveSkillStorage(req, { isImage });
-    return storage.saveBuffer({ userId, buffer, fileName, basePath }).then((filepath) => ({
-      filepath,
-      source: storage.source,
-    }));
+    return storage
+      .saveBuffer({ userId, buffer, fileName, basePath, tenantId: req.user.tenantId })
+      .then((filepath) => ({
+        filepath,
+        source: storage.source,
+      }));
   },
   deleteFile: (req, file) => {
     const { deleteFile } = getStrategyFunctions(file.source);
@@ -195,6 +197,7 @@ async function uploadFileHandler(req, res) {
       buffer: file.buffer,
       fileName: storageFileName,
       basePath: 'uploads',
+      tenantId: req.user.tenantId,
     });
 
     let result;
@@ -216,7 +219,7 @@ async function uploadFileHandler(req, res) {
       try {
         const { deleteFile } = getStrategyFunctions(storage.source);
         if (deleteFile) {
-          await deleteFile(req, { filepath });
+          await deleteFile(req, { filepath, user: req.user.id, tenantId: req.user.tenantId });
         }
       } catch (cleanupErr) {
         logger.error('[uploadFile] Failed to clean up orphaned blob:', cleanupErr);
@@ -228,9 +231,11 @@ async function uploadFileHandler(req, res) {
     if (existingFile && existingFile.filepath !== filepath) {
       const { deleteFile: delOld } = getStrategyFunctions(existingFile.source);
       if (delOld) {
-        delOld(req, { filepath: existingFile.filepath }).catch((e) =>
-          logger.error('[uploadFile] Old blob cleanup failed:', e),
-        );
+        delOld(req, {
+          filepath: existingFile.filepath,
+          user: existingFile.author ?? req.user.id,
+          tenantId: existingFile.tenantId ?? req.user.tenantId,
+        }).catch((e) => logger.error('[uploadFile] Old blob cleanup failed:', e));
       }
     }
 
diff --git a/api/server/services/AuthService.js b/api/server/services/AuthService.js
index 40b3c1a725..8053a605b4 100644
--- a/api/server/services/AuthService.js
+++ b/api/server/services/AuthService.js
@@ -12,6 +12,8 @@ const {
   isEnabled,
   checkEmailConfig,
   setCloudFrontCookies,
+  parseCloudFrontCookieScope,
+  CLOUDFRONT_SCOPE_COOKIE,
   isEmailDomainAllowed,
   shouldUseSecureCookie,
   resolveAppConfigForUser,
@@ -401,14 +403,23 @@ const resetPassword = async (userId, token, password) => {
   return { message: 'Password reset was successful' };
 };
 
+/**
+ * Reads the previously issued CloudFront cookie scope used for stale cookie cleanup.
+ * @param {ServerRequest | null} [req=null]
+ * @returns {import('@librechat/api').CloudFrontCookieScope | null}
+ */
+const getPreviousCloudFrontScope = (req) =>
+  parseCloudFrontCookieScope(req?.cookies?.[CLOUDFRONT_SCOPE_COOKIE]);
+
 /**
  * Set Auth Tokens
  * @param {String | ObjectId} userId
  * @param {ServerResponse} res
- * @param {ISession | null} [session=null]
+ * @param {ISession | null} [_session=null]
+ * @param {ServerRequest | null} [req=null]
  * @returns
  */
-const setAuthTokens = async (userId, res, _session = null) => {
+const setAuthTokens = async (userId, res, _session = null, req = null) => {
   try {
     let session = _session;
     let refreshToken;
@@ -442,7 +453,14 @@ const setAuthTokens = async (userId, res, _session = null) => {
       sameSite: 'strict',
     });
 
-    setCloudFrontCookies(res);
+    setCloudFrontCookies(
+      res,
+      {
+        userId: user?._id?.toString?.() ?? userId,
+        tenantId: user?.tenantId?.toString?.(),
+      },
+      getPreviousCloudFrontScope(req),
+    );
 
     return token;
   } catch (error) {
@@ -451,6 +469,21 @@ const setAuthTokens = async (userId, res, _session = null) => {
   }
 };
 
+const resolveOpenIDAuthTokenOptions = (optionsOrUserId, existingRefreshToken, tenantId) => {
+  if (optionsOrUserId != null && typeof optionsOrUserId === 'object') {
+    if (
+      'userId' in optionsOrUserId ||
+      'existingRefreshToken' in optionsOrUserId ||
+      'tenantId' in optionsOrUserId
+    ) {
+      return optionsOrUserId;
+    }
+    return {};
+  }
+
+  return { userId: optionsOrUserId, existingRefreshToken, tenantId };
+};
+
 /**
  * @function setOpenIDAuthTokens
  * Set OpenID Authentication Tokens
@@ -461,11 +494,27 @@ const setAuthTokens = async (userId, res, _session = null) => {
  * - The tokenset object containing access and refresh tokens
  * @param {Object} req - request object (for session access)
  * @param {Object} res - response object
- * @param {string} [userId] - Optional MongoDB user ID for image path validation
+ * @param {Object} [options] - Optional token/cookie context
+ * @param {string} [options.userId] - Optional MongoDB user ID for image path validation
+ * @param {string} [options.existingRefreshToken] - Optional existing refresh token to preserve
+ * @param {string} [options.tenantId] - Optional tenant identifier for CloudFront cookie scoping
  * @returns {String} - id_token (preferred) or access_token as the app auth token
  */
-const setOpenIDAuthTokens = (tokenset, req, res, userId, existingRefreshToken) => {
+const setOpenIDAuthTokens = (
+  tokenset,
+  req,
+  res,
+  optionsOrUserId = null,
+  existingRefreshTokenArg,
+  tenantIdArg,
+) => {
   try {
+    const { userId, existingRefreshToken, tenantId } = resolveOpenIDAuthTokenOptions(
+      optionsOrUserId,
+      existingRefreshTokenArg,
+      tenantIdArg,
+    );
+
     if (!tokenset) {
       logger.error('[setOpenIDAuthTokens] No tokenset found in request');
       return;
@@ -475,10 +524,6 @@ const setOpenIDAuthTokens = (tokenset, req, res, userId, existingRefreshToken) =
       DEFAULT_REFRESH_TOKEN_EXPIRY,
     );
     const expirationDate = new Date(Date.now() + expiryInMilliseconds);
-    if (tokenset == null) {
-      logger.error('[setOpenIDAuthTokens] No tokenset found in request');
-      return;
-    }
     if (!tokenset.access_token) {
       logger.error('[setOpenIDAuthTokens] No access token found in tokenset');
       return;
@@ -562,7 +607,14 @@ const setOpenIDAuthTokens = (tokenset, req, res, userId, existingRefreshToken) =
       });
     }
 
-    setCloudFrontCookies(res);
+    setCloudFrontCookies(
+      res,
+      {
+        userId,
+        tenantId: tenantId ?? req.user?.tenantId,
+      },
+      getPreviousCloudFrontScope(req),
+    );
 
     return appAuthToken;
   } catch (error) {
diff --git a/api/server/services/AuthService.spec.js b/api/server/services/AuthService.spec.js
index df89f3f2c9..cf893e1d6f 100644
--- a/api/server/services/AuthService.spec.js
+++ b/api/server/services/AuthService.spec.js
@@ -16,6 +16,8 @@ jest.mock('@librechat/api', () => ({
   shouldUseSecureCookie: jest.fn(() => false),
   resolveAppConfigForUser: jest.fn(async (_getAppConfig, _user) => ({})),
   setCloudFrontCookies: jest.fn(() => true),
+  parseCloudFrontCookieScope: jest.fn(() => null),
+  CLOUDFRONT_SCOPE_COOKIE: 'LibreChat-CloudFront-Scope',
 }));
 jest.mock('~/models', () => ({
   findUser: jest.fn(),
@@ -42,6 +44,7 @@ const {
   isEmailDomainAllowed,
   resolveAppConfigForUser,
   setCloudFrontCookies,
+  parseCloudFrontCookieScope,
 } = require('@librechat/api');
 const {
   findUser,
@@ -66,9 +69,10 @@ function mockResponse() {
 }
 
 /** Helper to build a mock Express request with session */
-function mockRequest(sessionData = {}) {
+function mockRequest(sessionData = {}, cookies = {}) {
   return {
     session: { openidTokens: null, ...sessionData },
+    cookies,
   };
 }
 
@@ -360,13 +364,90 @@ describe('CloudFront cookie integration', () => {
       refresh_token: 'the-refresh-token',
     };
 
-    it('calls setCloudFrontCookies with response object', () => {
+    it('calls setCloudFrontCookies with response object and user scope from options', () => {
       const req = mockRequest();
       const res = mockResponse();
 
-      setOpenIDAuthTokens(validTokenset, req, res, 'user-123');
+      setOpenIDAuthTokens(validTokenset, req, res, {
+        userId: 'user-123',
+        tenantId: 'tenantA',
+      });
 
-      expect(setCloudFrontCookies).toHaveBeenCalledWith(res);
+      expect(setCloudFrontCookies).toHaveBeenCalledWith(
+        res,
+        {
+          userId: 'user-123',
+          tenantId: 'tenantA',
+        },
+        null,
+      );
+    });
+
+    it('keeps backward compatibility with positional user and tenant params', () => {
+      const req = mockRequest();
+      const res = mockResponse();
+
+      setOpenIDAuthTokens(validTokenset, req, res, 'user-123', undefined, 'tenantA');
+
+      expect(setCloudFrontCookies).toHaveBeenCalledWith(
+        res,
+        {
+          userId: 'user-123',
+          tenantId: 'tenantA',
+        },
+        null,
+      );
+    });
+
+    it('treats a null options argument as an empty legacy user id', () => {
+      const req = mockRequest();
+      const res = mockResponse();
+
+      const result = setOpenIDAuthTokens(validTokenset, req, res, null);
+
+      expect(result).toBe('the-id-token');
+      expect(setCloudFrontCookies).toHaveBeenCalledWith(
+        res,
+        {
+          userId: null,
+          tenantId: undefined,
+        },
+        null,
+      );
+    });
+
+    it('treats omitted options as an empty legacy user id', () => {
+      const req = mockRequest();
+      const res = mockResponse();
+
+      const result = setOpenIDAuthTokens(validTokenset, req, res);
+
+      expect(result).toBe('the-id-token');
+      expect(setCloudFrontCookies).toHaveBeenCalledWith(
+        res,
+        {
+          userId: null,
+          tenantId: undefined,
+        },
+        null,
+      );
+    });
+
+    it('treats an object without token option keys as empty options', () => {
+      const req = mockRequest();
+      const res = mockResponse();
+
+      const result = setOpenIDAuthTokens(validTokenset, req, res, {});
+
+      expect(result).toBe('the-id-token');
+      expect(setCloudFrontCookies).toHaveBeenCalledWith(
+        res,
+        {
+          userId: undefined,
+          tenantId: undefined,
+        },
+        null,
+      );
     });
 
     it('succeeds even when setCloudFrontCookies returns false', () => {
@@ -383,7 +464,7 @@ describe('CloudFront cookie integration', () => {
 
   describe('setAuthTokens', () => {
     beforeEach(() => {
-      getUserById.mockResolvedValue({ _id: 'user-123' });
+      getUserById.mockResolvedValue({ _id: 'user-123', tenantId: 'tenantA' });
       generateToken.mockResolvedValue('mock-access-token');
       generateRefreshToken.mockReturnValue('mock-refresh-token');
       createSession.mockResolvedValue({
@@ -392,12 +473,37 @@ describe('CloudFront cookie integration', () => {
       });
     });
 
-    it('calls setCloudFrontCookies with response object', async () => {
+    it('calls setCloudFrontCookies with response object and user scope', async () => {
       const res = mockResponse();
 
       await setAuthTokens('user-123', res);
 
-      expect(setCloudFrontCookies).toHaveBeenCalledWith(res);
+      expect(setCloudFrontCookies).toHaveBeenCalledWith(
+        res,
+        {
+          userId: 'user-123',
+          tenantId: 'tenantA',
+        },
+        null,
+      );
+    });
+
+    it('passes the previous CloudFront cookie scope when present', async () => {
+      parseCloudFrontCookieScope.mockReturnValue({ userId: 'old-user', tenantId: 'old-tenant' });
+      const res = mockResponse();
+      const req = mockRequest({}, { 'LibreChat-CloudFront-Scope': 'encoded-scope' });
+
+      await setAuthTokens('user-123', res, null, req);
+
+      expect(parseCloudFrontCookieScope).toHaveBeenCalledWith('encoded-scope');
+      expect(setCloudFrontCookies).toHaveBeenCalledWith(
+        res,
+        {
+          userId: 'user-123',
+          tenantId: 'tenantA',
+        },
+        { userId: 'old-user', tenantId: 'old-tenant' },
+      );
     });
 
     it('succeeds even when setCloudFrontCookies returns false', async () => {
diff --git a/api/server/services/Files/Code/__tests__/process-traversal.spec.js b/api/server/services/Files/Code/__tests__/process-traversal.spec.js
index b6fcc2636f..6392e5b8bd 100644
--- a/api/server/services/Files/Code/__tests__/process-traversal.spec.js
+++ b/api/server/services/Files/Code/__tests__/process-traversal.spec.js
@@ -86,7 +86,7 @@ const { processCodeOutput } = require('../process');
 
 const baseParams = {
   req: {
-    user: { id: 'user123' },
+    user: { id: 'user123', tenantId: 'tenantA' },
     config: {
       fileStrategy: 'local',
       imageOutputType: 'webp',
@@ -129,6 +129,7 @@ describe('processCodeOutput path traversal protection', () => {
 
     const fileArg = createFile.mock.calls[0][0];
     expect(fileArg.filename).toBe('safe-output.csv');
+    expect(fileArg.tenantId).toBe('tenantA');
   });
 
   test('sanitized name is used for image file records', async () => {
@@ -144,5 +145,6 @@ describe('processCodeOutput path traversal protection', () => {
     expect(mockSanitizeArtifactPath).toHaveBeenCalledWith('../../../chart.png');
     const fileArg = createFile.mock.calls[0][0];
     expect(fileArg.filename).toBe('safe-chart.png');
+    expect(fileArg.tenantId).toBe('tenantA');
   });
 });
diff --git a/api/server/services/Files/Code/process.js b/api/server/services/Files/Code/process.js
index 4efc938223..c8d63cc919 100644
--- a/api/server/services/Files/Code/process.js
+++ b/api/server/services/Files/Code/process.js
@@ -396,6 +396,7 @@ const processCodeOutput = async ({
       conversationId,
       file_id: newFileId,
       user: req.user.id,
+      tenantId: req.user.tenantId,
     });
     const file_id = claimed.file_id;
     const isUpdate = file_id !== newFileId;
@@ -429,6 +430,7 @@ const processCodeOutput = async ({
         filename: safeName,
         conversationId,
         user: req.user.id,
+        tenantId: req.user.tenantId,
         type: `image/${appConfig.imageOutputType}`,
         createdAt: isUpdate ? claimed.createdAt : formattedDate,
         updatedAt: formattedDate,
@@ -490,6 +492,7 @@ const processCodeOutput = async ({
       buffer,
       fileName,
       basePath: 'uploads',
+      tenantId: req.user.tenantId,
     });
 
     /* `classifyCodeArtifact` and `extractCodeArtifactText` make
@@ -523,6 +526,7 @@ const processCodeOutput = async ({
       type: mimeType,
       conversationId,
       user: req.user.id,
+      tenantId: req.user.tenantId,
       bytes: buffer.length,
       updatedAt: formattedDate,
       metadata: { fileIdentifier },
diff --git a/api/server/services/Files/Code/process.spec.js b/api/server/services/Files/Code/process.spec.js
index 98cbbf9fff..7ca7799bfb 100644
--- a/api/server/services/Files/Code/process.spec.js
+++ b/api/server/services/Files/Code/process.spec.js
@@ -245,6 +245,29 @@ describe('Code Process', () => {
         expect(result.filename).toBe('chart.png');
       });
 
+      it('persists tenantId on image code output records when present', async () => {
+        const tenantReq = { ...mockReq, user: { ...mockReq.user, tenantId: 'tenantA' } };
+        const imageBuffer = Buffer.alloc(500);
+        mockAxios.mockResolvedValue({ data: imageBuffer });
+        convertImage.mockResolvedValue({
+          filepath: '/t/tenantA/images/user-123/mock-uuid-1234.webp',
+        });
+
+        await processCodeOutput({
+          ...baseParams,
+          req: tenantReq,
+          name: 'chart.png',
+        });
+
+        expect(mockClaimCodeFile).toHaveBeenCalledWith(
+          expect.objectContaining({ tenantId: 'tenantA' }),
+        );
+        expect(createFile).toHaveBeenCalledWith(
+          expect.objectContaining({ tenantId: 'tenantA' }),
+          true,
+        );
+      });
+
       it('should update existing image file with cache-busted filepath', async () => {
         const imageParams = { ...baseParams, name: 'chart.png' };
         mockClaimCodeFile.mockResolvedValue({
@@ -296,6 +319,33 @@ describe('Code Process', () => {
         expect(result.bytes).toBe(100);
       });
 
+      it('passes and persists tenantId for non-image code output records', async () => {
+        const tenantReq = { ...mockReq, user: { ...mockReq.user, tenantId: 'tenantA' } };
+        const smallBuffer = Buffer.alloc(100);
+        mockAxios.mockResolvedValue({ data: smallBuffer });
+
+        const mockSaveBuffer = jest
+          .fn()
+          .mockResolvedValue('/t/tenantA/uploads/user-123/mock-file-path.txt');
+        getStrategyFunctions.mockReturnValue({ saveBuffer: mockSaveBuffer });
+
+        await processCodeOutput({
+          ...baseParams,
+          req: tenantReq,
+        });
+
+        expect(mockClaimCodeFile).toHaveBeenCalledWith(
+          expect.objectContaining({ tenantId: 'tenantA' }),
+        );
+        expect(mockSaveBuffer).toHaveBeenCalledWith(
+          expect.objectContaining({ tenantId: 'tenantA' }),
+        );
+        expect(createFile).toHaveBeenCalledWith(
+          expect.objectContaining({ tenantId: 'tenantA' }),
+          true,
+        );
+      });
+
       it('preserves nested directory paths in the DB record while flattening the storage key', async () => {
         /* Regression test for the silent-data-loss path: when codeapi reports a
          * file with a nested name like "test_folder/test_file.txt", LibreChat
diff --git a/api/server/services/Files/images/convert.js b/api/server/services/Files/images/convert.js
index d5f5c2893b..dd0d795448 100644
--- a/api/server/services/Files/images/convert.js
+++ b/api/server/services/Files/images/convert.js
@@ -58,6 +58,7 @@ async function convertImage(req, file, resolution = 'high', basename = '') {
       userId: req.user.id,
       buffer: outputBuffer,
       fileName: newFileName,
+      tenantId: req.user.tenantId,
     });
 
     const bytes = Buffer.byteLength(outputBuffer);
diff --git a/api/server/services/Files/process.js b/api/server/services/Files/process.js
index 07c101fc33..057d3e531d 100644
--- a/api/server/services/Files/process.js
+++ b/api/server/services/Files/process.js
@@ -245,18 +245,44 @@ const processDeleteRequest = async ({ req, files }) => {
  * @param {string} params.fileName - The name that will be used to save the file (including extension)
  * @param {string} params.basePath - The base path or directory where the file will be saved or retrieved from.
  * @param {FileContext} params.context - The context of the file (e.g., 'avatar', 'image_generation', etc.)
+ * @param {string} [params.tenantId] - Optional tenant identifier for tenant-prefixed storage paths.
  * @returns {Promise<MongoFile>} A promise that resolves to the DB representation (MongoFile)
  *  of the processed file. It throws an error if the file processing fails at any stage.
  */
-const processFileURL = async ({ fileStrategy, userId, URL, fileName, basePath, context }) => {
+const processFileURL = async ({
+  fileStrategy,
+  userId,
+  URL,
+  fileName,
+  basePath,
+  context,
+  tenantId,
+}) => {
   const { saveURL, getFileURL } = getStrategyFunctions(fileStrategy);
   try {
+    const savedFile = await saveURL({ userId, URL, fileName, basePath, tenantId });
+    if (!savedFile) {
+      throw new Error(`Strategy "${fileStrategy}" did not save "${fileName}"`);
+    }
+
     const {
       bytes = 0,
       type = '',
       dimensions = {},
-    } = (await saveURL({ userId, URL, fileName, basePath })) || {};
-    const filepath = await getFileURL({ fileName: `${userId}/${fileName}`, basePath });
+    } = typeof savedFile === 'string' ? {} : savedFile;
+    const fallbackFileName =
+      fileStrategy === FileSources.local || fileStrategy === FileSources.firebase
+        ? `${userId}/${fileName}`
+        : fileName;
+    const filepath =
+      typeof savedFile === 'string'
+        ? savedFile
+        : (savedFile.filepath ??
+          (await getFileURL({ userId, fileName: fallbackFileName, basePath, tenantId })));
+    if (!filepath) {
+      throw new Error(`Strategy "${fileStrategy}" did not return a file URL for "${fileName}"`);
+    }
+
     return await db.createFile(
       {
         user: userId,
@@ -267,6 +293,7 @@ const processFileURL = async ({ fileStrategy, userId, URL, fileName, basePath, c
         source: fileStrategy,
         type,
         context,
+        tenantId,
         width: dimensions.width,
         height: dimensions.height,
       },
@@ -316,6 +343,7 @@ const processImageFile = async ({ req, res, metadata, returnFile = false }) => {
       type: `image/${appConfig.imageOutputType}`,
       width,
       height,
+      tenantId: req.user.tenantId,
     },
     true,
   );
@@ -354,7 +382,12 @@ const uploadImageBuffer = async ({ req, context, metadata = {}, resize = true })
     }`;
   }
   const fileName = `${file_id}-${filename}`;
-  const filepath = await saveBuffer({ userId: req.user.id, fileName, buffer });
+  const filepath = await saveBuffer({
+    userId: req.user.id,
+    fileName,
+    buffer,
+    tenantId: req.user.tenantId,
+  });
   return await db.createFile(
     {
       user: req.user.id,
@@ -367,6 +400,7 @@ const uploadImageBuffer = async ({ req, context, metadata = {}, resize = true })
       type,
       width,
       height,
+      tenantId: req.user.tenantId,
     },
     true,
   );
@@ -456,6 +490,7 @@ const processFileUpload = async ({ req, res, metadata }) => {
       source,
       height,
       width,
+      tenantId: req.user.tenantId,
     },
     true,
   );
@@ -546,6 +581,7 @@ const processAgentFileUpload = async ({ req, res, metadata }) => {
         filename: file.originalname,
         model: messageAttachment ? undefined : req.body.model,
         context: messageAttachment ? FileContext.message_attachment : FileContext.agents,
+        tenantId: req.user.tenantId,
       });
 
       if (!messageAttachment && tool_resource) {
@@ -722,6 +758,7 @@ const processAgentFileUpload = async ({ req, res, metadata }) => {
     source,
     height,
     width,
+    tenantId: req.user.tenantId,
   });
 
   const result = await db.createFile(fileInfo, true);
@@ -767,6 +804,7 @@ const processOpenAIFile = async ({
     source,
     model: openai.req.body.model,
     filename: originalName ?? file_id,
+    tenantId: openai.req?.user?.tenantId,
   };
 
   if (saveFile) {
@@ -810,6 +848,7 @@ const processOpenAIImageOutput = async ({ req, buffer, file_id, filename, fileEx
     context: FileContext.assistants_output,
     file_id,
     filename,
+    tenantId: req.user.tenantId,
   };
   db.createFile(file, true);
   return file;
@@ -954,6 +993,7 @@ async function saveBase64Image(
     userId: req.user.id,
     fileName: filename,
     buffer: image.buffer,
+    tenantId: req.user.tenantId,
   });
   return await db.createFile(
     {
@@ -967,6 +1007,7 @@ async function saveBase64Image(
       bytes: image.bytes,
       width: image.width,
       height: image.height,
+      tenantId: req.user.tenantId,
     },
     true,
   );
diff --git a/api/server/services/Files/process.spec.js b/api/server/services/Files/process.spec.js
index 88f2bb7b6b..02d12673e0 100644
--- a/api/server/services/Files/process.spec.js
+++ b/api/server/services/Files/process.spec.js
@@ -68,11 +68,17 @@ jest.mock('~/server/services/Files/Audio/STTService', () => ({
   STTService: { getInstance: jest.fn() },
 }));
 
-const { EToolResources, FileSources, AgentCapabilities } = require('librechat-data-provider');
+const {
+  EToolResources,
+  FileSources,
+  FileContext,
+  AgentCapabilities,
+} = require('librechat-data-provider');
 const { mergeFileConfig } = require('librechat-data-provider');
 const { checkCapability } = require('~/server/services/Config');
 const { getStrategyFunctions } = require('~/server/services/Files/strategies');
-const { processAgentFileUpload } = require('./process');
+const db = require('~/models');
+const { processAgentFileUpload, processFileURL } = require('./process');
 
 const PDF_MIME = 'application/pdf';
 const DOCX_MIME = 'application/vnd.openxmlformats-officedocument.wordprocessingml.document';
@@ -84,7 +90,7 @@ const ODP_MIME = 'application/vnd.oasis.opendocument.presentation';
 const ODG_MIME = 'application/vnd.oasis.opendocument.graphics';
 
 const makeReq = ({ mimetype = PDF_MIME, ocrConfig = null } = {}) => ({
-  user: { id: 'user-123' },
+  user: { id: 'user-123', tenantId: 'tenant-a' },
   file: {
     path: '/tmp/upload.bin',
     originalname: 'upload.bin',
@@ -340,3 +346,136 @@ describe('processAgentFileUpload', () => {
     });
   });
 });
+
+describe('processFileURL', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('throws and skips DB persistence when saveURL returns null', async () => {
+    const saveURL = jest.fn().mockResolvedValue(null);
+    const getFileURL = jest.fn();
+    getStrategyFunctions.mockReturnValue({ saveURL, getFileURL });
+
+    await expect(
+      processFileURL({
+        fileStrategy: FileSources.local,
+        userId: 'user-123',
+        URL: 'https://example.com/image.png',
+        fileName: 'image.png',
+        basePath: 'images',
+        context: FileContext.image_generation,
+        tenantId: 'tenant-a',
+      }),
+    ).rejects.toThrow('Strategy "local" did not save "image.png"');
+
+    expect(getFileURL).not.toHaveBeenCalled();
+    expect(db.createFile).not.toHaveBeenCalled();
+  });
+
+  it('persists tenantId and strategy-returned filepath metadata', async () => {
+    const saveURL = jest.fn().mockResolvedValue({
+      filepath: 'https://cdn.example.com/t/tenant-a/images/user-123/image.png',
+      bytes: 512,
+      type: 'image/png',
+      dimensions: { width: 32, height: 64 },
+    });
+    const getFileURL = jest.fn();
+    getStrategyFunctions.mockReturnValue({ saveURL, getFileURL });
+
+    await processFileURL({
+      fileStrategy: FileSources.cloudfront,
+      userId: 'user-123',
+      URL: 'https://example.com/image.png',
+      fileName: 'image.png',
+      basePath: 'images',
+      context: FileContext.image_generation,
+      tenantId: 'tenant-a',
+    });
+
+    expect(getFileURL).not.toHaveBeenCalled();
+    expect(db.createFile).toHaveBeenCalledWith(
+      expect.objectContaining({
+        user: 'user-123',
+        filepath: 'https://cdn.example.com/t/tenant-a/images/user-123/image.png',
+        bytes: 512,
+        filename: 'image.png',
+        source: FileSources.cloudfront,
+        type: 'image/png',
+        context: FileContext.image_generation,
+        tenantId: 'tenant-a',
+        width: 32,
+        height: 64,
+      }),
+      true,
+    );
+  });
+
+  it('falls back to getFileURL with user and tenant context when metadata lacks filepath', async () => {
+    const saveURL = jest.fn().mockResolvedValue({
+      bytes: 256,
+      type: 'image/png',
+    });
+    const getFileURL = jest
+      .fn()
+      .mockResolvedValue('https://cdn.example.com/t/tenant-a/images/user-123/image.png');
+    getStrategyFunctions.mockReturnValue({ saveURL, getFileURL });
+
+    await processFileURL({
+      fileStrategy: FileSources.cloudfront,
+      userId: 'user-123',
+      URL: 'https://example.com/image.png',
+      fileName: 'image.png',
+      basePath: 'images',
+      context: FileContext.image_generation,
+      tenantId: 'tenant-a',
+    });
+
+    expect(getFileURL).toHaveBeenCalledWith({
+      userId: 'user-123',
+      fileName: 'image.png',
+      basePath: 'images',
+      tenantId: 'tenant-a',
+    });
+    expect(db.createFile).toHaveBeenCalledWith(
+      expect.objectContaining({
+        filepath: 'https://cdn.example.com/t/tenant-a/images/user-123/image.png',
+        tenantId: 'tenant-a',
+      }),
+      true,
+    );
+  });
+
+  it('preserves the user path segment for local fallback URLs', async () => {
+    const saveURL = jest.fn().mockResolvedValue({
+      bytes: 256,
+      type: 'image/png',
+    });
+    const getFileURL = jest.fn().mockResolvedValue('/images/user-123/image.png');
+    getStrategyFunctions.mockReturnValue({ saveURL, getFileURL });
+
+    await processFileURL({
+      fileStrategy: FileSources.local,
+      userId: 'user-123',
+      URL: 'https://example.com/image.png',
+      fileName: 'image.png',
+      basePath: 'images',
+      context: FileContext.image_generation,
+      tenantId: 'tenant-a',
+    });
+
+    expect(getFileURL).toHaveBeenCalledWith({
+      userId: 'user-123',
+      fileName: 'user-123/image.png',
+      basePath: 'images',
+      tenantId: 'tenant-a',
+    });
+    expect(db.createFile).toHaveBeenCalledWith(
+      expect.objectContaining({
+        filepath: '/images/user-123/image.png',
+        tenantId: 'tenant-a',
+      }),
+      true,
+    );
+  });
+});
diff --git a/api/server/services/Files/strategies.js b/api/server/services/Files/strategies.js
index 8a88e9d2e1..e5acbd6903 100644
--- a/api/server/services/Files/strategies.js
+++ b/api/server/services/Files/strategies.js
@@ -1,20 +1,22 @@
 const { FileSources } = require('librechat-data-provider');
 const {
   getS3URL,
-  saveURLToS3,
+  saveURLToS3WithMetadata,
   ImageService,
   parseDocument,
   uploadFileToS3,
   saveBufferToS3,
   getS3FileStream,
+  getS3DownloadURL,
   deleteFileFromS3,
   getCloudFrontURL,
   uploadMistralOCR,
-  saveURLToCloudFront,
+  saveURLToCloudFrontWithMetadata,
   uploadAzureMistralOCR,
   uploadFileToCloudFront,
   saveBufferToCloudFront,
   getCloudFrontFileStream,
+  getCloudFrontDownloadURL,
   deleteFileFromCloudFront,
   uploadGoogleVertexMistralOCR,
 } = require('@librechat/api');
@@ -111,7 +113,7 @@ const localStrategy = () => ({
  * */
 const s3Strategy = () => ({
   handleFileUpload: uploadFileToS3,
-  saveURL: saveURLToS3,
+  saveURL: saveURLToS3WithMetadata,
   getFileURL: getS3URL,
   deleteFile: deleteFileFromS3,
   saveBuffer: saveBufferToS3,
@@ -119,6 +121,7 @@ const s3Strategy = () => ({
   processAvatar: processS3Avatar,
   handleImageUpload: uploadImageToS3,
   getDownloadStream: getS3FileStream,
+  getDownloadURL: getS3DownloadURL,
 });
 
 /**
@@ -127,7 +130,7 @@ const s3Strategy = () => ({
  */
 const cloudfrontStrategy = () => ({
   handleFileUpload: uploadFileToCloudFront,
-  saveURL: saveURLToCloudFront,
+  saveURL: saveURLToCloudFrontWithMetadata,
   getFileURL: getCloudFrontURL,
   deleteFile: deleteFileFromCloudFront,
   saveBuffer: saveBufferToCloudFront,
@@ -135,6 +138,7 @@ const cloudfrontStrategy = () => ({
   processAvatar: processCloudFrontAvatar,
   handleImageUpload: uploadImageToCloudFront,
   getDownloadStream: getCloudFrontFileStream,
+  getDownloadURL: getCloudFrontDownloadURL,
 });
 
 /**
diff --git a/api/strategies/openidStrategy.js b/api/strategies/openidStrategy.js
index 6d08fa1e59..595c2b535a 100644
--- a/api/strategies/openidStrategy.js
+++ b/api/strategies/openidStrategy.js
@@ -17,6 +17,8 @@ const {
   getOpenIdIssuer,
   getBalanceConfig,
   isEmailDomainAllowed,
+  getAvatarFileStrategy,
+  getAvatarSaveParams,
   resolveAppConfigForUser,
 } = require('@librechat/api');
 const { getStrategyFunctions } = require('~/server/services/Files/strategies');
@@ -662,14 +664,16 @@ async function processOpenIDAuth(tokenset, existingUsersOnly = false) {
       userinfo.sub,
     );
     if (imageBuffer) {
-      const { saveBuffer } = getStrategyFunctions(
-        appConfig?.fileStrategy ?? process.env.CDN_PROVIDER,
+      const fileStrategy = getAvatarFileStrategy(appConfig, process.env.CDN_PROVIDER);
+      const { saveBuffer } = getStrategyFunctions(fileStrategy);
+      const imagePath = await saveBuffer(
+        getAvatarSaveParams(fileStrategy, {
+          fileName,
+          userId: user._id.toString(),
+          buffer: imageBuffer,
+          tenantId: user.tenantId,
+        }),
       );
-      const imagePath = await saveBuffer({
-        fileName,
-        userId: user._id.toString(),
-        buffer: imageBuffer,
-      });
       user.avatar = imagePath ?? '';
     }
   }
diff --git a/api/strategies/openidStrategy.spec.js b/api/strategies/openidStrategy.spec.js
index 2812341e5c..15e507e9b5 100644
--- a/api/strategies/openidStrategy.spec.js
+++ b/api/strategies/openidStrategy.spec.js
@@ -1,7 +1,7 @@
 const undici = require('undici');
 const fetch = require('node-fetch');
 const jwtDecode = require('jsonwebtoken/decode');
-const { ErrorTypes } = require('librechat-data-provider');
+const { ErrorTypes, FileSources } = require('librechat-data-provider');
 const { findUser, createUser, updateUser } = require('~/models');
 const { getOpenIdIssuer, resolveAppConfigForUser } = require('@librechat/api');
 const { getAppConfig } = require('~/server/services/Config');
@@ -1097,15 +1097,50 @@ describe('setupOpenId', () => {
   });
 
   it('should attempt to download and save the avatar if picture is provided', async () => {
+    const { getStrategyFunctions } = require('~/server/services/Files/strategies');
+
     // Act
     const { user } = await validate(tokenset);
+    const strategyResult =
+      getStrategyFunctions.mock.results[getStrategyFunctions.mock.results.length - 1];
+    const { saveBuffer } = strategyResult.value;
+    const [saveParams] = saveBuffer.mock.calls[0];
 
     // Assert – verify that download was attempted and the avatar field was set via updateUser
     expect(fetch).toHaveBeenCalled();
+    expect(saveParams).toEqual(
+      expect.objectContaining({
+        fileName: 'hashed-token.png',
+        userId: 'newUserId',
+        buffer: expect.any(Buffer),
+      }),
+    );
+    expect(saveParams).not.toHaveProperty('basePath');
     // Our mock getStrategyFunctions.saveBuffer returns '/fake/path/to/avatar.png'
     expect(user.avatar).toBe('/fake/path/to/avatar.png');
   });
 
+  it('should save CloudFront IdP avatars under the shared avatar prefix', async () => {
+    const { getStrategyFunctions } = require('~/server/services/Files/strategies');
+    getAppConfig.mockResolvedValueOnce({ fileStrategy: FileSources.cloudfront });
+
+    const { user } = await validate(tokenset);
+    const strategyResult =
+      getStrategyFunctions.mock.results[getStrategyFunctions.mock.results.length - 1];
+    const { saveBuffer } = strategyResult.value;
+    const [saveParams] = saveBuffer.mock.calls[0];
+
+    expect(getStrategyFunctions).toHaveBeenLastCalledWith(FileSources.cloudfront);
+    expect(saveParams).toEqual(
+      expect.objectContaining({
+        basePath: 'avatars',
+        fileName: 'hashed-token.png',
+        userId: 'newUserId',
+      }),
+    );
+    expect(user.avatar).toBe('/fake/path/to/avatar.png');
+  });
+
   it('should not attempt to download avatar if picture is not provided', async () => {
     // Arrange – remove picture
     const userinfo = { ...tokenset.claims() };
diff --git a/api/strategies/samlStrategy.js b/api/strategies/samlStrategy.js
index 4f4bfac158..b21a4a482b 100644
--- a/api/strategies/samlStrategy.js
+++ b/api/strategies/samlStrategy.js
@@ -8,6 +8,8 @@ const { Strategy: SamlStrategy } = require('@node-saml/passport-saml');
 const {
   getBalanceConfig,
   isEmailDomainAllowed,
+  getAvatarFileStrategy,
+  getAvatarSaveParams,
   resolveAppConfigForUser,
 } = require('@librechat/api');
 const { getStrategyFunctions } = require('~/server/services/Files/strategies');
@@ -271,14 +273,16 @@ function createSamlCallback(existingUsersOnly = false) {
             fileName = profile.nameID + '.png';
           }
 
-          const { saveBuffer } = getStrategyFunctions(
-            appConfig?.fileStrategy ?? process.env.CDN_PROVIDER,
+          const fileStrategy = getAvatarFileStrategy(appConfig, process.env.CDN_PROVIDER);
+          const { saveBuffer } = getStrategyFunctions(fileStrategy);
+          const imagePath = await saveBuffer(
+            getAvatarSaveParams(fileStrategy, {
+              fileName,
+              userId: user._id.toString(),
+              buffer: imageBuffer,
+              tenantId: user.tenantId,
+            }),
           );
-          const imagePath = await saveBuffer({
-            fileName,
-            userId: user._id.toString(),
-            buffer: imageBuffer,
-          });
           user.avatar = imagePath ?? '';
         }
       }
diff --git a/api/strategies/samlStrategy.spec.js b/api/strategies/samlStrategy.spec.js
index 965fb157ef..dbf003e58c 100644
--- a/api/strategies/samlStrategy.spec.js
+++ b/api/strategies/samlStrategy.spec.js
@@ -30,6 +30,19 @@ jest.mock('@librechat/api', () => ({
     tokenCredits: 1000,
     startBalance: 1000,
   })),
+  getAvatarFileStrategy: jest.fn((config, fallbackStrategy) => {
+    const { FileSources } = jest.requireActual('librechat-data-provider');
+    if (config?.fileStrategies) {
+      return config.fileStrategies.avatar ?? config.fileStrategies.default ?? config.fileStrategy;
+    }
+    return config?.fileStrategy ?? fallbackStrategy ?? FileSources.local;
+  }),
+  getAvatarSaveParams: jest.fn((strategy, params) => {
+    const { FileSources } = jest.requireActual('librechat-data-provider');
+    return strategy === FileSources.s3 || strategy === FileSources.cloudfront
+      ? { ...params, basePath: 'avatars' }
+      : params;
+  }),
   resolveAppConfigForUser: jest.fn(async (_getAppConfig, _user) => ({})),
 }));
 jest.mock('~/server/services/Config/EndpointService', () => ({
@@ -48,6 +61,7 @@ const fs = require('fs');
 const path = require('path');
 const fetch = require('node-fetch');
 const { Strategy: SamlStrategy } = require('@node-saml/passport-saml');
+const { FileSources } = require('librechat-data-provider');
 const { findUser } = require('~/models');
 const { resolveAppConfigForUser } = require('@librechat/api');
 const { getAppConfig } = require('~/server/services/Config');
@@ -434,11 +448,46 @@ u7wlOSk+oFzDIO/UILIA
   });
 
   it('should attempt to download and save the avatar if picture is provided', async () => {
+    const { getStrategyFunctions } = require('~/server/services/Files/strategies');
     const profile = { ...baseProfile };
 
     const { user } = await validate(profile);
+    const strategyResult =
+      getStrategyFunctions.mock.results[getStrategyFunctions.mock.results.length - 1];
+    const { saveBuffer } = strategyResult.value;
+    const [saveParams] = saveBuffer.mock.calls[0];
 
     expect(fetch).toHaveBeenCalled();
+    expect(saveParams).toEqual(
+      expect.objectContaining({
+        fileName: 'hashed-token.png',
+        userId: 'mock-user-id',
+        buffer: expect.any(Buffer),
+      }),
+    );
+    expect(saveParams).not.toHaveProperty('basePath');
+    expect(user.avatar).toBe('/fake/path/to/avatar.png');
+  });
+
+  it('should save CloudFront SAML avatars under the shared avatar prefix', async () => {
+    const { getStrategyFunctions } = require('~/server/services/Files/strategies');
+    getAppConfig.mockResolvedValueOnce({ fileStrategies: { avatar: FileSources.cloudfront } });
+    const profile = { ...baseProfile };
+
+    const { user } = await validate(profile);
+    const strategyResult =
+      getStrategyFunctions.mock.results[getStrategyFunctions.mock.results.length - 1];
+    const { saveBuffer } = strategyResult.value;
+    const [saveParams] = saveBuffer.mock.calls[0];
+
+    expect(getStrategyFunctions).toHaveBeenLastCalledWith(FileSources.cloudfront);
+    expect(saveParams).toEqual(
+      expect.objectContaining({
+        basePath: 'avatars',
+        fileName: 'hashed-token.png',
+        userId: 'mock-user-id',
+      }),
+    );
     expect(user.avatar).toBe('/fake/path/to/avatar.png');
   });
 
diff --git a/client/src/components/Chat/Messages/Content/FilePreviewDialog.tsx b/client/src/components/Chat/Messages/Content/FilePreviewDialog.tsx
index c02e2fee4b..43e0abd7d6 100644
--- a/client/src/components/Chat/Messages/Content/FilePreviewDialog.tsx
+++ b/client/src/components/Chat/Messages/Content/FilePreviewDialog.tsx
@@ -5,7 +5,7 @@ import { Download } from 'lucide-react';
 import { OGDialog, OGDialogContent, OGDialogTitle, OGDialogDescription } from '@librechat/client';
 import CopyButton from '~/components/Messages/Content/CopyButton';
 import { logger, sortPagesByRelevance } from '~/utils';
-import { useFileDownload } from '~/data-provider';
+import { revokeDownloadURL, useFileDownload } from '~/data-provider';
 import { useLocalize } from '~/hooks';
 import store from '~/store';
 
@@ -136,7 +136,7 @@ export default function FilePreviewDialog({
 }: FilePreviewDialogProps) {
   const localize = useLocalize();
   const user = useRecoilValue(store.user);
-  const { refetch: downloadFile } = useFileDownload(user?.id ?? '', fileId);
+  const { refetch: downloadFile } = useFileDownload(user?.id ?? '', fileId, { direct: false });
 
   const [fileContent, setFileContent] = useState<string | null>(null);
   const [fileBlobUrl, setFileBlobUrl] = useState<string | null>(null);
@@ -207,7 +207,7 @@ export default function FilePreviewDialog({
       document.body.appendChild(a);
       a.click();
       document.body.removeChild(a);
-      setTimeout(() => URL.revokeObjectURL(result.data), 1000);
+      setTimeout(() => revokeDownloadURL(result.data), 1000);
     } catch (err) {
       logger.error('[FilePreviewDialog] Download failed:', err);
     }
diff --git a/client/src/components/Chat/Messages/Content/MarkdownComponents.tsx b/client/src/components/Chat/Messages/Content/MarkdownComponents.tsx
index 1f2a3ff594..e98b648013 100644
--- a/client/src/components/Chat/Messages/Content/MarkdownComponents.tsx
+++ b/client/src/components/Chat/Messages/Content/MarkdownComponents.tsx
@@ -5,7 +5,7 @@ import { PermissionTypes, Permissions, apiBaseUrl } from 'librechat-data-provide
 import Mermaid, { MermaidErrorBoundary } from '~/components/Messages/Content/Mermaid';
 import CodeBlock from '~/components/Messages/Content/CodeBlock';
 import useHasAccess from '~/hooks/Roles/useHasAccess';
-import { useFileDownload } from '~/data-provider';
+import { revokeDownloadURL, useFileDownload } from '~/data-provider';
 import { useCodeBlockContext } from '~/Providers';
 import { handleDoubleClick } from '~/utils';
 import { useLocalize } from '~/hooks';
@@ -127,7 +127,7 @@ export const a: React.ElementType = memo(function MarkdownAnchor({ href, childre
     return { file_id: '', filename: '', filepath: '' };
   }, [user?.id, href]);
 
-  const { refetch: downloadFile } = useFileDownload(user?.id ?? '', file_id);
+  const { refetch: downloadFile } = useFileDownload(user?.id ?? '', file_id, { direct: false });
   const props: { target?: string; onClick?: React.MouseEventHandler } = { target: '_blank' };
 
   if (!file_id || !filename) {
@@ -156,7 +156,7 @@ export const a: React.ElementType = memo(function MarkdownAnchor({ href, childre
       document.body.appendChild(link);
       link.click();
       document.body.removeChild(link);
-      window.URL.revokeObjectURL(stream.data);
+      revokeDownloadURL(stream.data);
     } catch (error) {
       console.error('Error downloading file:', error);
     }
diff --git a/client/src/components/Chat/Messages/Content/Parts/LogLink.tsx b/client/src/components/Chat/Messages/Content/Parts/LogLink.tsx
index 070becf517..d45e3d38d4 100644
--- a/client/src/components/Chat/Messages/Content/Parts/LogLink.tsx
+++ b/client/src/components/Chat/Messages/Content/Parts/LogLink.tsx
@@ -1,7 +1,7 @@
 import React from 'react';
 import { FileSources } from 'librechat-data-provider';
 import { useToastContext } from '@librechat/client';
-import { useCodeOutputDownload, useFileDownload } from '~/data-provider';
+import { revokeDownloadURL, useCodeOutputDownload, useFileDownload } from '~/data-provider';
 
 interface LogLinkProps {
   href: string;
@@ -29,9 +29,13 @@ const isLocallyStoredSource = (source?: string): boolean => {
   if (!source) {
     return false;
   }
-  return [FileSources.local, FileSources.firebase, FileSources.s3, FileSources.azure_blob].includes(
-    source as FileSources,
-  );
+  return [
+    FileSources.local,
+    FileSources.firebase,
+    FileSources.s3,
+    FileSources.cloudfront,
+    FileSources.azure_blob,
+  ].includes(source as FileSources);
 };
 
 export const useAttachmentLink = ({
@@ -44,7 +48,7 @@ export const useAttachmentLink = ({
   const { showToast } = useToastContext();
 
   const useLocalDownload = isLocallyStoredSource(source) && !!file_id && !!user;
-  const { refetch: downloadFromApi } = useFileDownload(user, file_id);
+  const { refetch: downloadFromApi } = useFileDownload(user, file_id, { source });
   const { refetch: downloadFromUrl } = useCodeOutputDownload(href);
 
   const handleDownload = async (event: React.MouseEvent<HTMLAnchorElement | HTMLButtonElement>) => {
@@ -65,7 +69,7 @@ export const useAttachmentLink = ({
       document.body.appendChild(link);
       link.click();
       document.body.removeChild(link);
-      window.URL.revokeObjectURL(stream.data);
+      revokeDownloadURL(stream.data);
     } catch (error) {
       console.error('Error downloading file:', error);
     }
diff --git a/client/src/components/Web/Sources.tsx b/client/src/components/Web/Sources.tsx
index 97e646d5d0..06f8a576b0 100644
--- a/client/src/components/Web/Sources.tsx
+++ b/client/src/components/Web/Sources.tsx
@@ -16,7 +16,7 @@ import {
 import type { ValidSource, ImageResult } from 'librechat-data-provider';
 import { FaviconImage, getCleanDomain } from '~/components/Web/SourceHovercard';
 import SourcesErrorBoundary from './SourcesErrorBoundary';
-import { useFileDownload } from '~/data-provider';
+import { revokeDownloadURL, useFileDownload } from '~/data-provider';
 import { useSearchContext } from '~/Providers';
 import { useLocalize } from '~/hooks';
 import { cn } from '~/utils';
@@ -212,7 +212,9 @@ const FileItem = React.memo(function FileItem({
   const user = useRecoilValue(store.user);
   const { showToast } = useToastContext();
 
-  const { refetch: downloadFile } = useFileDownload(user?.id ?? '', file.file_id);
+  const { refetch: downloadFile } = useFileDownload(user?.id ?? '', file.file_id, {
+    source: file.source,
+  });
 
   // Extract error message logic to avoid duplication
   const getErrorMessage = useCallback(
@@ -261,7 +263,7 @@ const FileItem = React.memo(function FileItem({
         document.body.appendChild(link);
         link.click();
         document.body.removeChild(link);
-        window.URL.revokeObjectURL(stream.data);
+        revokeDownloadURL(stream.data);
       } catch (error) {
         console.error('Error downloading file:', error);
       }
diff --git a/client/src/data-provider/Files/__tests__/previewRefetchInterval.spec.ts b/client/src/data-provider/Files/__tests__/previewRefetchInterval.spec.ts
index b23d8f996d..cc0fc2f22f 100644
--- a/client/src/data-provider/Files/__tests__/previewRefetchInterval.spec.ts
+++ b/client/src/data-provider/Files/__tests__/previewRefetchInterval.spec.ts
@@ -1,3 +1,4 @@
+import { FileSources } from 'librechat-data-provider';
 import type { TFilePreview } from 'librechat-data-provider';
 
 const mockGetFilePreview = jest.fn();
@@ -16,7 +17,9 @@ import {
   PREVIEW_MAX_CONSECUTIVE_ERRORS,
   _resetPreviewErrorCounter,
   fetchFilePreview,
+  isDirectDownloadSource,
   previewRefetchInterval,
+  revokeDownloadURL,
 } from '../queries';
 
 const q = (fileId: string) => ({ queryKey: ['filePreview' as const, fileId] });
@@ -95,3 +98,26 @@ describe('previewRefetchInterval', () => {
     expect(previewRefetchInterval(undefined, q('fid-healthy'))).toBe(2500);
   });
 });
+
+describe('download URL helpers', () => {
+  it('uses direct download URLs only for strategies that implement them', () => {
+    expect(isDirectDownloadSource(FileSources.s3)).toBe(true);
+    expect(isDirectDownloadSource(FileSources.cloudfront)).toBe(true);
+    expect(isDirectDownloadSource(FileSources.local)).toBe(false);
+    expect(isDirectDownloadSource(FileSources.firebase)).toBe(false);
+    expect(isDirectDownloadSource(undefined)).toBe(false);
+  });
+
+  it('revokes only blob URLs', () => {
+    const originalRevokeObjectURL = window.URL.revokeObjectURL;
+    const revokeObjectURL = jest.fn();
+    window.URL.revokeObjectURL = revokeObjectURL;
+
+    revokeDownloadURL('https://cdn.example.com/file.pdf');
+    revokeDownloadURL('blob:https://app.example.com/id');
+
+    expect(revokeObjectURL).toHaveBeenCalledTimes(1);
+    expect(revokeObjectURL).toHaveBeenCalledWith('blob:https://app.example.com/id');
+    window.URL.revokeObjectURL = originalRevokeObjectURL;
+  });
+});
diff --git a/client/src/data-provider/Files/queries.ts b/client/src/data-provider/Files/queries.ts
index 8502704676..db02bfb64b 100644
--- a/client/src/data-provider/Files/queries.ts
+++ b/client/src/data-provider/Files/queries.ts
@@ -1,6 +1,6 @@
 import { useRecoilValue } from 'recoil';
 import { useQuery, useQueryClient } from '@tanstack/react-query';
-import { QueryKeys, DynamicQueryKeys, dataService } from 'librechat-data-provider';
+import { FileSources, QueryKeys, DynamicQueryKeys, dataService } from 'librechat-data-provider';
 import type { QueryObserverResult, UseQueryOptions } from '@tanstack/react-query';
 import type t from 'librechat-data-provider';
 import { isEphemeralAgent } from '~/common';
@@ -53,15 +53,45 @@ export const useGetFileConfig = <TData = t.FileConfig>(
   );
 };
 
-export const useFileDownload = (userId?: string, file_id?: string): QueryObserverResult<string> => {
+type FileDownloadOptions = {
+  source?: string | null;
+  direct?: boolean;
+};
+
+export const isDirectDownloadSource = (source?: string | null): boolean =>
+  source === FileSources.s3 || source === FileSources.cloudfront;
+
+export const revokeDownloadURL = (url?: string | null): void => {
+  if (!url?.startsWith('blob:')) {
+    return;
+  }
+  window.URL.revokeObjectURL(url);
+};
+
+export const useFileDownload = (
+  userId?: string,
+  file_id?: string,
+  options: FileDownloadOptions = {},
+): QueryObserverResult<string> => {
   const queryClient = useQueryClient();
   return useQuery(
-    [QueryKeys.fileDownload, file_id],
+    [QueryKeys.fileDownload, file_id, options.source ?? '', options.direct ?? true],
     async () => {
       if (!userId || !file_id) {
         console.warn('No user ID provided for file download');
         return;
       }
+      if ((options.direct ?? true) && isDirectDownloadSource(options.source)) {
+        try {
+          const directDownload = await dataService.getFileDownloadURL(userId, file_id);
+          if (directDownload.url) {
+            return directDownload.url;
+          }
+        } catch {
+          // Fall back to the legacy proxied download for direct URL failures.
+        }
+      }
+
       const response = await dataService.getFileDownload(userId, file_id);
       const blob = response.data;
       const downloadURL = window.URL.createObjectURL(blob);
diff --git a/librechat.example.yaml b/librechat.example.yaml
index dd275718a2..963189584c 100644
--- a/librechat.example.yaml
+++ b/librechat.example.yaml
@@ -29,17 +29,25 @@ cache: true
 # CloudFront CDN Configuration (optional)
 # Use when fileStrategy: "cloudfront" or fileStrategies includes cloudfront
 # Requires: AWS_REGION, AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_BUCKET_NAME
-# For signed cookies/URLs: CLOUDFRONT_KEY_PAIR_ID, CLOUDFRONT_PRIVATE_KEY
+# For signed cookies and direct download URLs: CLOUDFRONT_KEY_PAIR_ID, CLOUDFRONT_PRIVATE_KEY
 # cloudfront:
 #   domain: "https://cdn.example.com"       # CloudFront domain (CNAME recommended for cookies)
 #   distributionId: "E1234ABCD"             # Required if invalidateOnDelete is true
 #   invalidateOnDelete: false               # Create cache invalidation on file delete
 #   imageSigning: "none"                    # "none" (public) | "cookies" (signed cookies)
-#   # When imageSigning: "cookies", API + CloudFront must share a parent domain:
+#   # When imageSigning: "cookies", API + CloudFront must share a parent domain.
+#   # Cookies are path-scoped to private image prefixes and avatar prefixes.
+#   # If adding tenantId to a private pre-release CloudFront deployment, re-key
+#   # legacy /images and /avatars objects under /t/{tenantId}/ before enabling.
 #   #   API: api.example.com, CloudFront CNAME: cdn.example.com, cookieDomain: ".example.com"
 #   cookieDomain: ".example.com"            # Required for "cookies" - shared parent domain
 #   cookieExpiry: 1800                      # Cookie lifetime in seconds (max: 604800 / 7 days, default: 1800 / 30 min)
-#   urlExpiry: 3600                         # Reserved for future signed-URL mode (not yet implemented)
+#   urlExpiry: 3600                         # Signed CloudFront download URL lifetime in seconds
+#   # Direct-download filename/content-type overrides require the CloudFront cache/origin
+#   # request policy to forward and cache on response-content-disposition and
+#   # response-content-type query strings to S3.
+#   # Recommended for download paths: attach a CloudFront response headers policy
+#   # with X-Content-Type-Options: nosniff and CSP default-src 'none'.
 
 # Custom interface configuration
 interface:
diff --git a/packages/api/src/cdn/__tests__/cloudfront-cookies.test.ts b/packages/api/src/cdn/__tests__/cloudfront-cookies.test.ts
index 73f0e25872..fcfd63d1f8 100644
--- a/packages/api/src/cdn/__tests__/cloudfront-cookies.test.ts
+++ b/packages/api/src/cdn/__tests__/cloudfront-cookies.test.ts
@@ -16,31 +16,43 @@ jest.mock('@librechat/data-schemas', () => ({
 }));
 
 import type { Response } from 'express';
-import { setCloudFrontCookies, clearCloudFrontCookies } from '../cloudfront-cookies';
+import {
+  setCloudFrontCookies,
+  clearCloudFrontCookies,
+  parseCloudFrontCookieScope,
+} from '../cloudfront-cookies';
 
 const { logger: mockLogger } = jest.requireMock('@librechat/data-schemas') as {
   logger: { warn: jest.Mock; error: jest.Mock; info: jest.Mock; debug: jest.Mock };
 };
 
+const defaultScope = { userId: 'user123' };
+
 describe('setCloudFrontCookies', () => {
   let mockRes: Partial<Response>;
   let cookieArgs: Array<[string, string, object]>;
+  let clearedCookies: Array<[string, object]>;
 
   beforeEach(() => {
     jest.clearAllMocks();
     cookieArgs = [];
+    clearedCookies = [];
     mockRes = {
       cookie: jest.fn((name: string, value: string, options: object) => {
         cookieArgs.push([name, value, options]);
         return mockRes as Response;
       }) as unknown as Response['cookie'],
+      clearCookie: jest.fn((name: string, options: object) => {
+        clearedCookies.push([name, options]);
+        return mockRes as Response;
+      }) as unknown as Response['clearCookie'],
     };
   });
 
   it('returns false when CloudFront config is null', () => {
     mockGetCloudFrontConfig.mockReturnValue(null);
 
-    const result = setCloudFrontCookies(mockRes as Response);
+    const result = setCloudFrontCookies(mockRes as Response, defaultScope);
 
     expect(result).toBe(false);
     expect(mockRes.cookie).not.toHaveBeenCalled();
@@ -55,7 +67,7 @@ describe('setCloudFrontCookies', () => {
       keyPairId: 'K123',
     });
 
-    const result = setCloudFrontCookies(mockRes as Response);
+    const result = setCloudFrontCookies(mockRes as Response, defaultScope);
 
     expect(result).toBe(false);
     expect(mockRes.cookie).not.toHaveBeenCalled();
@@ -70,7 +82,7 @@ describe('setCloudFrontCookies', () => {
       keyPairId: null,
     });
 
-    const result = setCloudFrontCookies(mockRes as Response);
+    const result = setCloudFrontCookies(mockRes as Response, defaultScope);
 
     expect(result).toBe(false);
     expect(mockRes.cookie).not.toHaveBeenCalled();
@@ -85,7 +97,7 @@ describe('setCloudFrontCookies', () => {
       keyPairId: 'K123ABC',
     });
 
-    const result = setCloudFrontCookies(mockRes as Response);
+    const result = setCloudFrontCookies(mockRes as Response, defaultScope);
 
     expect(result).toBe(false);
     expect(mockRes.cookie).not.toHaveBeenCalled();
@@ -107,7 +119,7 @@ describe('setCloudFrontCookies', () => {
       'CloudFront-Key-Pair-Id': 'K123ABC',
     });
 
-    const result = setCloudFrontCookies(mockRes as Response);
+    const result = setCloudFrontCookies(mockRes as Response, defaultScope);
 
     expect(result).toBe(true);
     expect(mockLogger.warn).not.toHaveBeenCalled();
@@ -116,7 +128,7 @@ describe('setCloudFrontCookies', () => {
     expect(isNaN((options as { expires: Date }).expires.getTime())).toBe(false);
   });
 
-  it('sets three CloudFront cookies when enabled', () => {
+  it('sets separate CloudFront cookie sets for private images and avatars when enabled', () => {
     mockGetCloudFrontConfig.mockReturnValue({
       domain: 'https://cdn.example.com',
       imageSigning: 'cookies',
@@ -132,10 +144,11 @@ describe('setCloudFrontCookies', () => {
       'CloudFront-Key-Pair-Id': 'K123ABC',
     });
 
-    const result = setCloudFrontCookies(mockRes as Response);
+    const result = setCloudFrontCookies(mockRes as Response, defaultScope);
 
     expect(result).toBe(true);
-    expect(mockRes.cookie).toHaveBeenCalledTimes(3);
+    expect(mockRes.cookie).toHaveBeenCalledTimes(7);
+    expect(mockRes.clearCookie).toHaveBeenCalledTimes(6);
 
     const cookieNames = cookieArgs.map(([name]) => name);
     expect(cookieNames).toContain('CloudFront-Policy');
@@ -143,7 +156,7 @@ describe('setCloudFrontCookies', () => {
     expect(cookieNames).toContain('CloudFront-Key-Pair-Id');
   });
 
-  it('uses cookieDomain from config with path', () => {
+  it('uses cookieDomain from config with path-scoped cookies', () => {
     mockGetCloudFrontConfig.mockReturnValue({
       domain: 'https://cdn.example.com',
       imageSigning: 'cookies',
@@ -159,7 +172,7 @@ describe('setCloudFrontCookies', () => {
       'CloudFront-Key-Pair-Id': 'K123ABC',
     });
 
-    setCloudFrontCookies(mockRes as Response);
+    setCloudFrontCookies(mockRes as Response, defaultScope);
 
     const [, , options] = cookieArgs[0];
     expect(options).toMatchObject({
@@ -167,11 +180,12 @@ describe('setCloudFrontCookies', () => {
       secure: true,
       sameSite: 'none',
       domain: '.example.com',
-      path: '/images',
+      path: '/images/user123',
     });
+    expect(cookieArgs[3][2]).toMatchObject({ path: '/avatars' });
   });
 
-  it('builds correct custom policy for images resource', () => {
+  it('clears legacy image-wide and avatar cookie paths before setting scoped cookies', () => {
     mockGetCloudFrontConfig.mockReturnValue({
       domain: 'https://cdn.example.com',
       imageSigning: 'cookies',
@@ -187,15 +201,146 @@ describe('setCloudFrontCookies', () => {
       'CloudFront-Key-Pair-Id': 'K123ABC',
     });
 
-    setCloudFrontCookies(mockRes as Response);
+    setCloudFrontCookies(mockRes as Response, defaultScope);
 
+    expect(clearedCookies).toHaveLength(6);
+    expect(clearedCookies).toContainEqual([
+      'CloudFront-Policy',
+      expect.objectContaining({ path: '/images' }),
+    ]);
+    expect(clearedCookies).toContainEqual([
+      'CloudFront-Key-Pair-Id',
+      expect.objectContaining({ path: '/avatars' }),
+    ]);
+  });
+
+  it('clears the previously issued scoped cookie paths before setting new cookies', () => {
+    mockGetCloudFrontConfig.mockReturnValue({
+      domain: 'https://cdn.example.com',
+      imageSigning: 'cookies',
+      cookieExpiry: 1800,
+      cookieDomain: '.example.com',
+      privateKey: '-----BEGIN RSA PRIVATE KEY-----\ntest\n-----END RSA PRIVATE KEY-----',
+      keyPairId: 'K123ABC',
+    });
+
+    mockGetSignedCookies.mockReturnValue({
+      'CloudFront-Policy': 'policy-value',
+      'CloudFront-Signature': 'signature-value',
+      'CloudFront-Key-Pair-Id': 'K123ABC',
+    });
+
+    setCloudFrontCookies(
+      mockRes as Response,
+      { userId: 'newUser', tenantId: 'newTenant' },
+      { userId: 'oldUser', tenantId: 'oldTenant' },
+    );
+
+    expect(clearedCookies).toContainEqual([
+      'CloudFront-Policy',
+      expect.objectContaining({ path: '/t/oldTenant/images/oldUser' }),
+    ]);
+    expect(clearedCookies).toContainEqual([
+      'CloudFront-Signature',
+      expect.objectContaining({ path: '/t/oldTenant/avatars' }),
+    ]);
+  });
+
+  it('stores the issued CloudFront cookie scope for later cleanup', () => {
+    mockGetCloudFrontConfig.mockReturnValue({
+      domain: 'https://cdn.example.com',
+      imageSigning: 'cookies',
+      cookieExpiry: 1800,
+      cookieDomain: '.example.com',
+      privateKey: '-----BEGIN RSA PRIVATE KEY-----\ntest\n-----END RSA PRIVATE KEY-----',
+      keyPairId: 'K123ABC',
+    });
+
+    mockGetSignedCookies.mockReturnValue({
+      'CloudFront-Policy': 'policy-value',
+      'CloudFront-Signature': 'signature-value',
+      'CloudFront-Key-Pair-Id': 'K123ABC',
+    });
+
+    setCloudFrontCookies(mockRes as Response, { userId: 'user123', tenantId: 'tenantA' });
+
+    const [name, value, options] = cookieArgs[cookieArgs.length - 1];
+    expect(name).toBe('LibreChat-CloudFront-Scope');
+    expect(options).toMatchObject({ domain: '.example.com', path: '/' });
+    expect(Buffer.from(value, 'base64url').toString('utf8')).toBe(
+      JSON.stringify({ userId: 'user123', tenantId: 'tenantA' }),
+    );
+  });
+
+  it('builds user-scoped custom policies for private images and avatars', () => {
+    mockGetCloudFrontConfig.mockReturnValue({
+      domain: 'https://cdn.example.com',
+      imageSigning: 'cookies',
+      cookieExpiry: 1800,
+      cookieDomain: '.example.com',
+      privateKey: '-----BEGIN RSA PRIVATE KEY-----\ntest\n-----END RSA PRIVATE KEY-----',
+      keyPairId: 'K123ABC',
+    });
+
+    mockGetSignedCookies.mockReturnValue({
+      'CloudFront-Policy': 'policy-value',
+      'CloudFront-Signature': 'signature-value',
+      'CloudFront-Key-Pair-Id': 'K123ABC',
+    });
+
+    setCloudFrontCookies(mockRes as Response, defaultScope);
+
+    const privatePolicy = JSON.parse(mockGetSignedCookies.mock.calls[0][0].policy);
+    const avatarPolicy = JSON.parse(mockGetSignedCookies.mock.calls[1][0].policy);
+    expect(mockGetSignedCookies).toHaveBeenCalledTimes(2);
     expect(mockGetSignedCookies).toHaveBeenCalledWith(
       expect.objectContaining({
         keyPairId: 'K123ABC',
         privateKey: expect.stringContaining('BEGIN RSA PRIVATE KEY'),
-        policy: expect.stringContaining('https://cdn.example.com/images/*'),
       }),
     );
+    expect(privatePolicy.Statement).toEqual([
+      expect.objectContaining({ Resource: 'https://cdn.example.com/images/user123/*' }),
+    ]);
+    expect(avatarPolicy.Statement).toEqual([
+      expect.objectContaining({ Resource: 'https://cdn.example.com/avatars/*' }),
+    ]);
+  });
+
+  it('builds a tenant-scoped custom policy and cookie path', () => {
+    mockGetCloudFrontConfig.mockReturnValue({
+      domain: 'https://cdn.example.com',
+      imageSigning: 'cookies',
+      cookieExpiry: 1800,
+      cookieDomain: '.example.com',
+      privateKey: '-----BEGIN RSA PRIVATE KEY-----\ntest\n-----END RSA PRIVATE KEY-----',
+      keyPairId: 'K123ABC',
+    });
+
+    mockGetSignedCookies.mockReturnValue({
+      'CloudFront-Policy': 'policy-value',
+      'CloudFront-Signature': 'signature-value',
+      'CloudFront-Key-Pair-Id': 'K123ABC',
+    });
+
+    const result = setCloudFrontCookies(mockRes as Response, {
+      userId: 'user123',
+      tenantId: 'tenantA',
+    });
+
+    const privatePolicy = JSON.parse(mockGetSignedCookies.mock.calls[0][0].policy);
+    const avatarPolicy = JSON.parse(mockGetSignedCookies.mock.calls[1][0].policy);
+    expect(result).toBe(true);
+    expect(privatePolicy.Statement).toEqual([
+      expect.objectContaining({
+        Resource: 'https://cdn.example.com/t/tenantA/images/user123/*',
+      }),
+    ]);
+    expect(avatarPolicy.Statement).toEqual([
+      expect.objectContaining({ Resource: 'https://cdn.example.com/t/tenantA/avatars/*' }),
+    ]);
+    expect(cookieArgs[0][2]).toMatchObject({ path: '/t/tenantA/images/user123' });
+    expect(cookieArgs[3][2]).toMatchObject({ path: '/t/tenantA/avatars' });
   });
 
   it('handles multiple trailing slashes in domain', () => {
@@ -214,11 +359,11 @@ describe('setCloudFrontCookies', () => {
       'CloudFront-Key-Pair-Id': 'K123ABC',
     });
 
-    setCloudFrontCookies(mockRes as Response);
+    setCloudFrontCookies(mockRes as Response, defaultScope);
 
     expect(mockGetSignedCookies).toHaveBeenCalledWith(
       expect.objectContaining({
-        policy: expect.stringContaining('https://cdn.example.com/images/*'),
+        policy: expect.stringContaining('https://cdn.example.com/images/user123/*'),
       }),
     );
   });
@@ -235,10 +380,11 @@ describe('setCloudFrontCookies', () => {
 
     mockGetSignedCookies.mockReturnValue({});
 
-    const result = setCloudFrontCookies(mockRes as Response);
+    const result = setCloudFrontCookies(mockRes as Response, defaultScope);
 
     expect(result).toBe(false);
     expect(mockRes.cookie).not.toHaveBeenCalled();
+    expect(mockRes.clearCookie).not.toHaveBeenCalled();
     expect(mockLogger.error).toHaveBeenCalledWith(
       expect.stringContaining('Missing expected cookie from AWS SDK'),
     );
@@ -256,9 +402,50 @@ describe('setCloudFrontCookies', () => {
 
     mockGetSignedCookies.mockReturnValue({ 'CloudFront-Policy': 'policy-value' });
 
+    const result = setCloudFrontCookies(mockRes as Response, defaultScope);
+
+    expect(result).toBe(false);
+    expect(mockRes.cookie).not.toHaveBeenCalled();
+    expect(mockRes.clearCookie).not.toHaveBeenCalled();
+  });
+
+  it('returns false when userId is missing from scope', () => {
+    mockGetCloudFrontConfig.mockReturnValue({
+      domain: 'https://cdn.example.com',
+      imageSigning: 'cookies',
+      cookieExpiry: 1800,
+      cookieDomain: '.example.com',
+      privateKey: '-----BEGIN RSA PRIVATE KEY-----\ntest\n-----END RSA PRIVATE KEY-----',
+      keyPairId: 'K123ABC',
+    });
+
     const result = setCloudFrontCookies(mockRes as Response);
 
     expect(result).toBe(false);
+    expect(mockLogger.warn).toHaveBeenCalledWith(
+      '[setCloudFrontCookies] CloudFront configured but userId missing from scope',
+    );
+    expect(mockRes.cookie).not.toHaveBeenCalled();
+  });
+
+  it('returns false when scope path segments contain policy wildcards or traversal', () => {
+    mockGetCloudFrontConfig.mockReturnValue({
+      domain: 'https://cdn.example.com',
+      imageSigning: 'cookies',
+      cookieExpiry: 1800,
+      cookieDomain: '.example.com',
+      privateKey: '-----BEGIN RSA PRIVATE KEY-----\ntest\n-----END RSA PRIVATE KEY-----',
+      keyPairId: 'K123ABC',
+    });
+
+    expect(setCloudFrontCookies(mockRes as Response, { userId: 'user*' })).toBe(false);
+    expect(
+      setCloudFrontCookies(mockRes as Response, { userId: 'user123', tenantId: '../tenantA' }),
+    ).toBe(false);
+    expect(
+      setCloudFrontCookies(mockRes as Response, { userId: 'user123', tenantId: 'tenant A' }),
+    ).toBe(false);
+    expect(mockGetSignedCookies).not.toHaveBeenCalled();
     expect(mockRes.cookie).not.toHaveBeenCalled();
   });
 
@@ -277,7 +464,7 @@ describe('setCloudFrontCookies', () => {
       throw signingError;
     });
 
-    const result = setCloudFrontCookies(mockRes as Response);
+    const result = setCloudFrontCookies(mockRes as Response, defaultScope);
 
     expect(result).toBe(false);
     expect(mockRes.cookie).not.toHaveBeenCalled();
@@ -288,6 +475,36 @@ describe('setCloudFrontCookies', () => {
   });
 });
 
+describe('parseCloudFrontCookieScope', () => {
+  const encodeScope = (scope: object) =>
+    Buffer.from(JSON.stringify(scope), 'utf8').toString('base64url');
+
+  it('round-trips a valid user and tenant scope', () => {
+    const value = encodeScope({ userId: 'user123', tenantId: 'tenantA' });
+
+    expect(parseCloudFrontCookieScope(value)).toEqual({
+      userId: 'user123',
+      tenantId: 'tenantA',
+    });
+  });
+
+  it('returns null for empty, malformed, or userless values', () => {
+    expect(parseCloudFrontCookieScope(null)).toBeNull();
+    expect(parseCloudFrontCookieScope(undefined)).toBeNull();
+    expect(parseCloudFrontCookieScope('')).toBeNull();
+    expect(parseCloudFrontCookieScope('not-json')).toBeNull();
+    expect(parseCloudFrontCookieScope(encodeScope({ tenantId: 'tenantA' }))).toBeNull();
+  });
+
+  it('rejects traversal and wildcard path segments', () => {
+    expect(parseCloudFrontCookieScope(encodeScope({ userId: '../user' }))).toBeNull();
+    expect(parseCloudFrontCookieScope(encodeScope({ userId: 'user*' }))).toBeNull();
+    expect(
+      parseCloudFrontCookieScope(encodeScope({ userId: 'user123', tenantId: 'tenant A' })),
+    ).toBeNull();
+  });
+});
+
 describe('clearCloudFrontCookies', () => {
   let mockRes: Partial<Response>;
   let clearedCookies: Array<[string, object]>;
@@ -311,7 +528,7 @@ describe('clearCloudFrontCookies', () => {
     expect(mockRes.clearCookie).not.toHaveBeenCalled();
   });
 
-  it('does nothing when imageSigning is not "cookies"', () => {
+  it('clears stale cookies when imageSigning is not "cookies"', () => {
     mockGetCloudFrontConfig.mockReturnValue({
       domain: 'https://cdn.example.com',
       imageSigning: 'none',
@@ -320,7 +537,7 @@ describe('clearCloudFrontCookies', () => {
 
     clearCloudFrontCookies(mockRes as Response);
 
-    expect(mockRes.clearCookie).not.toHaveBeenCalled();
+    expect(mockRes.clearCookie).toHaveBeenCalledTimes(10);
   });
 
   it('does nothing when cookieDomain is missing', () => {
@@ -334,7 +551,7 @@ describe('clearCloudFrontCookies', () => {
     expect(mockRes.clearCookie).not.toHaveBeenCalled();
   });
 
-  it('clears all three CloudFront cookies with correct domain', () => {
+  it('clears all CloudFront cookies with correct domain and legacy paths', () => {
     mockGetCloudFrontConfig.mockReturnValue({
       domain: 'https://cdn.example.com',
       imageSigning: 'cookies',
@@ -345,21 +562,31 @@ describe('clearCloudFrontCookies', () => {
 
     clearCloudFrontCookies(mockRes as Response);
 
-    expect(mockRes.clearCookie).toHaveBeenCalledTimes(3);
+    expect(mockRes.clearCookie).toHaveBeenCalledTimes(10);
 
-    const expectedOptions = {
+    const legacyPathOptions = {
       domain: '.example.com',
       path: '/images',
       httpOnly: true,
       secure: true,
       sameSite: 'none',
     };
-    expect(clearedCookies).toContainEqual(['CloudFront-Policy', expectedOptions]);
-    expect(clearedCookies).toContainEqual(['CloudFront-Signature', expectedOptions]);
-    expect(clearedCookies).toContainEqual(['CloudFront-Key-Pair-Id', expectedOptions]);
+    const rootPathOptions = {
+      domain: '.example.com',
+      path: '/',
+      httpOnly: true,
+      secure: true,
+      sameSite: 'none',
+    };
+    expect(clearedCookies).toContainEqual(['CloudFront-Policy', legacyPathOptions]);
+    expect(clearedCookies).toContainEqual(['CloudFront-Signature', legacyPathOptions]);
+    expect(clearedCookies).toContainEqual(['CloudFront-Key-Pair-Id', legacyPathOptions]);
+    expect(clearedCookies).toContainEqual(['CloudFront-Policy', rootPathOptions]);
+    expect(clearedCookies).toContainEqual(['CloudFront-Signature', rootPathOptions]);
+    expect(clearedCookies).toContainEqual(['CloudFront-Key-Pair-Id', rootPathOptions]);
   });
 
-  it('clears cookies with full security attributes matching set path', () => {
+  it('clears tenant-scoped cookies', () => {
     mockGetCloudFrontConfig.mockReturnValue({
       domain: 'https://cdn.example.com',
       imageSigning: 'cookies',
@@ -368,20 +595,29 @@ describe('clearCloudFrontCookies', () => {
       keyPairId: 'K123',
     });
 
-    clearCloudFrontCookies(mockRes as Response);
+    clearCloudFrontCookies(mockRes as Response, { userId: 'user123', tenantId: 'tenantA' });
 
-    expect(mockRes.clearCookie).toHaveBeenCalledTimes(3);
-
-    const expectedOptions = {
-      domain: '.example.com',
-      path: '/images',
-      httpOnly: true,
-      secure: true,
-      sameSite: 'none',
-    };
-    expect(clearedCookies).toContainEqual(['CloudFront-Policy', expectedOptions]);
-    expect(clearedCookies).toContainEqual(['CloudFront-Signature', expectedOptions]);
-    expect(clearedCookies).toContainEqual(['CloudFront-Key-Pair-Id', expectedOptions]);
+    expect(mockRes.clearCookie).toHaveBeenCalledTimes(19);
+    expect(clearedCookies).toContainEqual([
+      'CloudFront-Policy',
+      {
+        domain: '.example.com',
+        path: '/t/tenantA/images/user123',
+        httpOnly: true,
+        secure: true,
+        sameSite: 'none',
+      },
+    ]);
+    expect(clearedCookies).toContainEqual([
+      'LibreChat-CloudFront-Scope',
+      {
+        domain: '.example.com',
+        path: '/',
+        httpOnly: true,
+        secure: true,
+        sameSite: 'none',
+      },
+    ]);
   });
 
   it('logs warning and does not throw when clearing fails', () => {
diff --git a/packages/api/src/cdn/__tests__/s3.test.ts b/packages/api/src/cdn/__tests__/s3.test.ts
index 9a522ecc4f..703ec40f86 100644
--- a/packages/api/src/cdn/__tests__/s3.test.ts
+++ b/packages/api/src/cdn/__tests__/s3.test.ts
@@ -62,6 +62,14 @@ describe('initializeS3', () => {
     );
   });
 
+  it('should only calculate request checksums when S3 requires them', async () => {
+    const { MockS3Client, initializeS3 } = await load();
+    initializeS3();
+    expect(MockS3Client).toHaveBeenCalledWith(
+      expect.objectContaining({ requestChecksumCalculation: 'WHEN_REQUIRED' }),
+    );
+  });
+
   it('should not include endpoint when AWS_ENDPOINT_URL is not set', async () => {
     const { MockS3Client, initializeS3 } = await load();
     initializeS3();
diff --git a/packages/api/src/cdn/cloudfront-cookies.ts b/packages/api/src/cdn/cloudfront-cookies.ts
index 8ed23dc1d1..b62b5533fd 100644
--- a/packages/api/src/cdn/cloudfront-cookies.ts
+++ b/packages/api/src/cdn/cloudfront-cookies.ts
@@ -1,8 +1,9 @@
-import { logger } from '@librechat/data-schemas';
 import { getSignedCookies } from '@aws-sdk/cloudfront-signer';
+import { logger } from '@librechat/data-schemas';
 
 import type { Response } from 'express';
 
+import { assertPathSegment } from '~/storage/validation';
 import { getCloudFrontConfig } from './cloudfront';
 
 const DEFAULT_COOKIE_EXPIRY = 1800;
@@ -13,26 +14,147 @@ const REQUIRED_CF_COOKIES = [
   'CloudFront-Key-Pair-Id',
 ] as const;
 
+export const CLOUDFRONT_SCOPE_COOKIE = 'LibreChat-CloudFront-Scope';
+const unsafePolicySegmentPattern = /[?*[\]\s]/;
+
+export interface CloudFrontCookieScope {
+  userId?: string | null;
+  tenantId?: string | null;
+}
+
+type CookieOptions = {
+  domain: string;
+  httpOnly: boolean;
+  secure: boolean;
+  sameSite: 'none';
+};
+
+function assertPolicyPathSegment(label: string, value: string | null | undefined): string {
+  const segment = assertPathSegment(label, value, 'CloudFront cookies');
+  if (unsafePolicySegmentPattern.test(segment)) {
+    throw new Error(`[CloudFront cookies] ${label} contains unsafe policy characters.`);
+  }
+  return segment;
+}
+
+function getPolicyScopes(
+  domain: string,
+  { userId, tenantId }: CloudFrontCookieScope,
+): Array<{ resource: string; path: string }> {
+  if (!userId) {
+    throw new Error('[CloudFront cookies] userId is required for private image access.');
+  }
+
+  const safeUserId = assertPolicyPathSegment('userId', userId);
+  if (tenantId) {
+    const safeTenantId = assertPolicyPathSegment('tenantId', tenantId);
+    return [
+      {
+        resource: `${domain}/t/${safeTenantId}/images/${safeUserId}/*`,
+        path: `/t/${safeTenantId}/images/${safeUserId}`,
+      },
+      { resource: `${domain}/t/${safeTenantId}/avatars/*`, path: `/t/${safeTenantId}/avatars` },
+    ];
+  }
+
+  return [
+    { resource: `${domain}/images/${safeUserId}/*`, path: `/images/${safeUserId}` },
+    { resource: `${domain}/avatars/*`, path: '/avatars' },
+  ];
+}
+
+function getScopeCookiePaths(
+  scope: CloudFrontCookieScope,
+  { includeTenantRoot = false }: { includeTenantRoot?: boolean } = {},
+): string[] {
+  if (!scope.userId) {
+    return [];
+  }
+
+  const safeUserId = assertPolicyPathSegment('userId', scope.userId);
+  if (scope.tenantId) {
+    const safeTenantId = assertPolicyPathSegment('tenantId', scope.tenantId);
+    const paths = [`/t/${safeTenantId}/images/${safeUserId}`, `/t/${safeTenantId}/avatars`];
+    if (includeTenantRoot) {
+      paths.push(`/t/${safeTenantId}`);
+    }
+    return paths;
+  }
+
+  return [`/images/${safeUserId}`, '/avatars'];
+}
+
+function encodeCloudFrontCookieScope(scope: CloudFrontCookieScope): string {
+  const payload = {
+    userId: scope.userId ?? null,
+    tenantId: scope.tenantId ?? null,
+  };
+  return Buffer.from(JSON.stringify(payload), 'utf8').toString('base64url');
+}
+
+export function parseCloudFrontCookieScope(
+  value: string | null | undefined,
+): CloudFrontCookieScope | null {
+  if (!value) {
+    return null;
+  }
+
+  try {
+    const parsed = JSON.parse(Buffer.from(value, 'base64url').toString('utf8')) as {
+      userId?: unknown;
+      tenantId?: unknown;
+    };
+    const scope: CloudFrontCookieScope = {};
+    if (typeof parsed.userId === 'string') {
+      scope.userId = assertPolicyPathSegment('userId', parsed.userId);
+    }
+    if (typeof parsed.tenantId === 'string') {
+      scope.tenantId = assertPolicyPathSegment('tenantId', parsed.tenantId);
+    }
+    return scope.userId ? scope : null;
+  } catch {
+    return null;
+  }
+}
+
+function clearCookiePaths(
+  res: Response,
+  baseOptions: CookieOptions,
+  paths: Iterable<string>,
+): void {
+  for (const path of paths) {
+    const options = { ...baseOptions, path };
+    for (const key of REQUIRED_CF_COOKIES) {
+      res.clearCookie(key, options);
+    }
+  }
+}
+
 /**
  * Clears CloudFront signed cookies from the response.
  * Should be called during logout to revoke CDN access.
  */
-export function clearCloudFrontCookies(res: Response): void {
+export function clearCloudFrontCookies(res: Response, scope: CloudFrontCookieScope = {}): void {
   try {
     const config = getCloudFrontConfig();
-    if (!config?.cookieDomain || config.imageSigning !== 'cookies') {
+    if (!config?.cookieDomain) {
       return;
     }
-    const options = {
+    const baseOptions = {
       domain: config.cookieDomain,
-      path: '/images',
       httpOnly: true,
       secure: true,
       sameSite: 'none' as const,
     };
-    res.clearCookie('CloudFront-Policy', options);
-    res.clearCookie('CloudFront-Signature', options);
-    res.clearCookie('CloudFront-Key-Pair-Id', options);
+    const paths = new Set(['/images', '/avatars', '/']);
+    if (scope.userId) {
+      for (const path of getScopeCookiePaths(scope, { includeTenantRoot: true })) {
+        paths.add(path);
+      }
+    }
+
+    clearCookiePaths(res, baseOptions, paths);
+    res.clearCookie(CLOUDFRONT_SCOPE_COOKIE, { ...baseOptions, path: '/' });
   } catch (error) {
     logger.warn('[clearCloudFrontCookies] Failed to clear cookies:', error);
   }
@@ -42,65 +164,104 @@ export function clearCloudFrontCookies(res: Response): void {
  * Sets CloudFront signed cookies on the response for CDN access.
  * Returns true if cookies were set, false if CloudFront cookies are not enabled.
  */
-export function setCloudFrontCookies(res: Response): boolean {
+export function setCloudFrontCookies(
+  res: Response,
+  scope: CloudFrontCookieScope = {},
+  previousScope: CloudFrontCookieScope | null = null,
+): boolean {
   const config = getCloudFrontConfig();
+  if (
+    config?.imageSigning === 'cookies' &&
+    config.privateKey &&
+    config.keyPairId &&
+    config.cookieDomain &&
+    !scope.userId
+  ) {
+    logger.warn('[setCloudFrontCookies] CloudFront configured but userId missing from scope');
+    return false;
+  }
   if (
     !config ||
     config.imageSigning !== 'cookies' ||
     !config.privateKey ||
     !config.keyPairId ||
-    !config.cookieDomain
+    !config.cookieDomain ||
+    !scope.userId
   ) {
     return false;
   }
 
   try {
+    const { keyPairId, privateKey } = config;
     const cookieExpiry = config.cookieExpiry ?? DEFAULT_COOKIE_EXPIRY;
     const expiresAtMs = Date.now() + cookieExpiry * 1000;
     const expiresAt = new Date(expiresAtMs);
     const expiresAtEpoch = Math.floor(expiresAtMs / 1000);
 
-    const resourceUrl = `${config.domain.replace(/\/+$/, '')}/images/*`;
-
-    const policy = JSON.stringify({
-      Statement: [
-        {
-          Resource: resourceUrl,
-          Condition: {
-            DateLessThan: {
-              'AWS:EpochTime': expiresAtEpoch,
+    const cleanDomain = config.domain.replace(/\/+$/, '');
+    const policyScopes = getPolicyScopes(cleanDomain, scope);
+    // CloudFront custom-policy cookies are scoped to one resource, so issue
+    // separate path-specific cookie sets for private files and shared avatars.
+    const signedCookieSets = policyScopes.map(({ resource, path }) => {
+      const policy = JSON.stringify({
+        Statement: [
+          {
+            Resource: resource,
+            Condition: {
+              DateLessThan: {
+                'AWS:EpochTime': expiresAtEpoch,
+              },
             },
           },
-        },
-      ],
+        ],
+      });
+
+      return {
+        path,
+        cookies: getSignedCookies({
+          keyPairId,
+          privateKey,
+          policy,
+        }),
+      };
     });
 
-    const signedCookies = getSignedCookies({
-      keyPairId: config.keyPairId,
-      privateKey: config.privateKey,
-      policy,
-    });
-
-    const cookieOptions = {
-      expires: expiresAt,
+    const sharedCookieOptions = {
       httpOnly: true,
       secure: true,
       sameSite: 'none' as const,
       domain: config.cookieDomain,
-      path: '/images',
     };
-
-    for (const key of REQUIRED_CF_COOKIES) {
-      if (!signedCookies[key]) {
-        logger.error(`[setCloudFrontCookies] Missing expected cookie from AWS SDK: ${key}`);
-        return false;
+    const stalePaths = new Set(['/images', '/avatars']);
+    if (previousScope?.userId) {
+      for (const path of getScopeCookiePaths(previousScope)) {
+        stalePaths.add(path);
       }
     }
 
-    for (const key of REQUIRED_CF_COOKIES) {
-      res.cookie(key, signedCookies[key], cookieOptions);
+    for (const { cookies } of signedCookieSets) {
+      for (const key of REQUIRED_CF_COOKIES) {
+        if (!cookies[key]) {
+          logger.error(`[setCloudFrontCookies] Missing expected cookie from AWS SDK: ${key}`);
+          return false;
+        }
+      }
     }
 
+    clearCookiePaths(res, sharedCookieOptions, stalePaths);
+    const baseCookieOptions = { ...sharedCookieOptions, expires: expiresAt };
+
+    for (const { cookies, path } of signedCookieSets) {
+      const cookieOptions = { ...baseCookieOptions, path };
+      for (const key of REQUIRED_CF_COOKIES) {
+        res.cookie(key, cookies[key], cookieOptions);
+      }
+    }
+    res.cookie(CLOUDFRONT_SCOPE_COOKIE, encodeCloudFrontCookieScope(scope), {
+      ...baseCookieOptions,
+      path: '/',
+    });
+
     return true;
   } catch (error) {
     logger.error('[setCloudFrontCookies] Failed to generate signed cookies:', error);
diff --git a/packages/api/src/cdn/s3.ts b/packages/api/src/cdn/s3.ts
index c2d0e4d1eb..475cf0aa69 100644
--- a/packages/api/src/cdn/s3.ts
+++ b/packages/api/src/cdn/s3.ts
@@ -39,6 +39,7 @@ export const initializeS3 = (): S3Client | null => {
 
   const config = {
     region,
+    requestChecksumCalculation: 'WHEN_REQUIRED' as const,
     ...(endpoint ? { endpoint } : {}),
     ...(isEnabled(process.env.AWS_FORCE_PATH_STYLE) ? { forcePathStyle: true } : {}),
   };
diff --git a/packages/api/src/files/code/form.ts b/packages/api/src/files/code/form.ts
index 6f9abab7d4..707cf72182 100644
--- a/packages/api/src/files/code/form.ts
+++ b/packages/api/src/files/code/form.ts
@@ -8,9 +8,7 @@ export interface CodeEnvFileOptions {
 }
 
 const CODE_ENV_SAFE_ASCII_FILEPATH_CHAR_PATTERN = /^[a-zA-Z0-9._\-/]$/;
-const CODE_ENV_UNSAFE_UNICODE_FILEPATH_CHAR_PATTERN =
-  /[^\p{L}\p{M}\p{N}\p{Emoji}\u200d._\-/]/u;
-const CODE_ENV_FILENAME_CONTROL_CHARS_PATTERN = /[\x00-\x1f\x7f]/g;
+const CODE_ENV_UNSAFE_UNICODE_FILEPATH_CHAR_PATTERN = /[^\p{L}\p{M}\p{N}\p{Emoji}\u200d._\-/]/u;
 
 function hasUnsafeCodeEnvFilepathChar(filepath: string): boolean {
   for (const char of filepath) {
@@ -49,7 +47,10 @@ function getCodeEnvBasename(filepath: string): string {
 }
 
 function getSafeCodeEnvFilename(filename: string): string {
-  return filename.replace(CODE_ENV_FILENAME_CONTROL_CHARS_PATTERN, '_');
+  return Array.from(filename, (char) => {
+    const code = char.charCodeAt(0);
+    return code <= 0x1f || code === 0x7f ? '_' : char;
+  }).join('');
 }
 
 /**
diff --git a/packages/api/src/skills/handlers.ts b/packages/api/src/skills/handlers.ts
index 5b713d4596..81982186aa 100644
--- a/packages/api/src/skills/handlers.ts
+++ b/packages/api/src/skills/handlers.ts
@@ -31,7 +31,7 @@ import type {
   TSkillConflictResponse,
   TSkillFileContentResponse,
 } from 'librechat-data-provider';
-import type { ServerRequest } from '~/types/http';
+import type { ServerRequest, StrategyFunctions } from '~/types';
 import { isBinaryBuffer } from './binary';
 
 /** Thin error shape the skill methods throw on validation failure. */
@@ -107,10 +107,7 @@ export interface SkillsHandlersDeps {
   ) => Promise<void>;
 
   /** Storage strategy resolver — returns stream/URL helpers keyed by source. */
-  getStrategyFunctions: (source: string) => {
-    getDownloadStream?: (req: ServerRequest, filepath: string) => Promise<NodeJS.ReadableStream>;
-    [key: string]: unknown;
-  };
+  getStrategyFunctions: (source: string) => Partial<StrategyFunctions>;
 
   /** ObjectId validation helper from data-schemas. */
   isValidObjectIdString: (value: unknown) => boolean;
@@ -288,19 +285,6 @@ export function createSkillsHandlers(deps: SkillsHandlersDeps) {
     isValidObjectIdString,
   } = deps;
 
-  async function getPublicSkillIdSet(): Promise<Set<string>> {
-    try {
-      const publicIds = await findPubliclyAccessibleResources({
-        resourceType: ResourceType.SKILL,
-        requiredPermissions: PermissionBits.VIEW,
-      });
-      return new Set(publicIds.map((id) => id.toString()));
-    } catch (error) {
-      logger.error('[skills] Failed to fetch public skill IDs', error);
-      return new Set();
-    }
-  }
-
   /** O(1) public check for a single skill (avoids fetching all public IDs). */
   async function isSkillPublic(skillId: string | Types.ObjectId): Promise<boolean> {
     try {
@@ -556,11 +540,13 @@ export function createSkillsHandlers(deps: SkillsHandlersDeps) {
 
       // Fire-and-forget blob cleanup for each file
       for (const file of files) {
-        const { deleteFile: deleteBlob } = getStrategyFunctions(file.source) as {
-          deleteFile?: (r: ServerRequest, f: { filepath: string }) => Promise<void>;
-        };
+        const { deleteFile: deleteBlob } = getStrategyFunctions(file.source);
         if (deleteBlob) {
-          deleteBlob(req, { filepath: file.filepath }).catch((e) =>
+          deleteBlob(req, {
+            filepath: file.filepath,
+            user: file.author?.toString?.(),
+            tenantId: file.tenantId?.toString?.(),
+          }).catch((e) =>
             logger.error(`[deleteSkill] Blob cleanup failed for ${file.relativePath}:`, e),
           );
         }
@@ -759,13 +745,13 @@ export function createSkillsHandlers(deps: SkillsHandlersDeps) {
       }
 
       // Clean up the stored blob — fire-and-forget so the response isn't delayed
-      const { deleteFile: deleteBlob } = getStrategyFunctions(file.source) as {
-        deleteFile?: (req: ServerRequest, file: { filepath: string }) => Promise<void>;
-      };
+      const { deleteFile: deleteBlob } = getStrategyFunctions(file.source);
       if (deleteBlob) {
-        deleteBlob(req, { filepath: file.filepath }).catch((e) =>
-          logger.error('[deleteFile] Storage cleanup failed:', e),
-        );
+        deleteBlob(req, {
+          filepath: file.filepath,
+          user: file.author?.toString?.(),
+          tenantId: file.tenantId?.toString?.(),
+        }).catch((e) => logger.error('[deleteFile] Storage cleanup failed:', e));
       }
 
       const response: TDeleteSkillFileResponse = {
diff --git a/packages/api/src/skills/import.ts b/packages/api/src/skills/import.ts
index f0223b8700..af6e0e3466 100644
--- a/packages/api/src/skills/import.ts
+++ b/packages/api/src/skills/import.ts
@@ -168,6 +168,7 @@ export interface ImportSkillDeps {
       fileName: string;
       basePath?: string;
       isImage?: boolean;
+      tenantId?: string;
     },
   ) => Promise<{ filepath: string; source: string }>;
   deleteFile?: (
@@ -524,6 +525,7 @@ async function handleZip(
         fileName: storageFileName,
         basePath: 'uploads',
         isImage: mimeType.startsWith('image/'),
+        tenantId,
       });
 
       // Upsert the SkillFile DB record (runs path validation internally).
@@ -545,7 +547,7 @@ async function handleZip(
       } catch (dbError) {
         if (deps.deleteFile) {
           await deps
-            .deleteFile(req, { filepath, source })
+            .deleteFile(req, { filepath, source, user: authorId, tenantId })
             .catch((e) =>
               logger.error(`[importSkill] Orphan cleanup failed for ${relativePath}:`, e),
             );
diff --git a/packages/api/src/storage/__tests__/images.test.ts b/packages/api/src/storage/__tests__/images.test.ts
index 9d151a1044..ec8f71910e 100644
--- a/packages/api/src/storage/__tests__/images.test.ts
+++ b/packages/api/src/storage/__tests__/images.test.ts
@@ -89,6 +89,7 @@ describe('ImageService', () => {
         buffer: expect.any(Buffer),
         fileName: expect.stringContaining('file-456__'),
         basePath: 'images',
+        tenantId: null,
       });
 
       expect(fs.promises.unlink).toHaveBeenCalledWith('/tmp/upload-123.jpg');
@@ -233,7 +234,8 @@ describe('ImageService', () => {
         userId: 'user123',
         buffer,
         fileName: expect.stringMatching(/^avatar-\d+\.png$/),
-        basePath: 'images',
+        basePath: 'avatars',
+        tenantId: null,
       });
       expect(mockDeps.updateUser).toHaveBeenCalledWith('user123', {
         avatar: 'https://storage.example.com/images/user123/file.webp',
@@ -270,6 +272,24 @@ describe('ImageService', () => {
       expect(mockDeps.updateUser).not.toHaveBeenCalled();
     });
 
+    it('passes tenantId through for avatar storage', async () => {
+      const buffer = Buffer.from('avatar-data');
+
+      await service.processAvatar({
+        buffer,
+        userId: 'user123',
+        manual: 'false',
+        tenantId: 'tenantA',
+      });
+
+      expect(mockSaveBuffer).toHaveBeenCalledWith(
+        expect.objectContaining({
+          basePath: 'avatars',
+          tenantId: 'tenantA',
+        }),
+      );
+    });
+
     it('appends manual param when config.appendManualParam is true', async () => {
       const serviceWithManualParam = new ImageService(mockSaveBuffer, mockDeps, {
         appendManualParam: true,
diff --git a/packages/api/src/storage/__tests__/validation.test.ts b/packages/api/src/storage/__tests__/validation.test.ts
new file mode 100644
index 0000000000..dafb172ac2
--- /dev/null
+++ b/packages/api/src/storage/__tests__/validation.test.ts
@@ -0,0 +1,69 @@
+import {
+  assertS3FileName,
+  assertPathSegment,
+  sanitizeContentDispositionFilename,
+} from '../validation';
+
+describe('assertPathSegment', () => {
+  it('returns safe single path segments', () => {
+    expect(assertPathSegment('userId', 'user123', 'test')).toBe('user123');
+  });
+
+  it('rejects empty, slash, traversal, and control-character segments', () => {
+    expect(() => assertPathSegment('userId', '', 'test')).toThrow('must not be empty');
+    expect(() => assertPathSegment('userId', null, 'test')).toThrow('must not be empty');
+    expect(() => assertPathSegment('userId', undefined, 'test')).toThrow('must not be empty');
+    expect(() => assertPathSegment('userId', 'user/123', 'test')).toThrow(
+      'must not contain slashes',
+    );
+    expect(() => assertPathSegment('userId', '..', 'test')).toThrow(
+      'must not contain path traversal',
+    );
+    expect(assertPathSegment('tenantId', 'tenant..legacy', 'test')).toBe('tenant..legacy');
+    expect(() => assertPathSegment('userId', 'user\u0000id', 'test')).toThrow(
+      'contains unsafe path characters',
+    );
+    expect(() => assertPathSegment('userId', 'user\u007fid', 'test')).toThrow(
+      'contains unsafe path characters',
+    );
+  });
+});
+
+describe('assertS3FileName', () => {
+  it('allows nested S3 file names', () => {
+    expect(assertS3FileName('fileName', 'reports/2026/output.csv', 'test')).toBe(
+      'reports/2026/output.csv',
+    );
+  });
+
+  it('rejects traversal, empty components, backslashes, and control characters', () => {
+    expect(() => assertS3FileName('fileName', '../secret.txt', 'test')).toThrow(
+      'must not contain path traversal',
+    );
+    expect(() => assertS3FileName('fileName', 'reports//output.csv', 'test')).toThrow(
+      'must not contain empty path components',
+    );
+    expect(() => assertS3FileName('fileName', 'reports\\output.csv', 'test')).toThrow(
+      'must not contain backslashes',
+    );
+    expect(() => assertS3FileName('fileName', 'report\u0000.csv', 'test')).toThrow(
+      'contains unsafe path characters',
+    );
+  });
+});
+
+describe('sanitizeContentDispositionFilename', () => {
+  it('strips quoted-string and header separator characters', () => {
+    expect(sanitizeContentDispositionFilename('report";\\\r\nbad.pdf')).toBe('reportbad.pdf');
+  });
+
+  it('strips all ASCII control characters from header filenames', () => {
+    expect(sanitizeContentDispositionFilename('report\u0000\t\u001fbad\u007f.pdf')).toBe(
+      'reportbad.pdf',
+    );
+  });
+
+  it('returns a safe fallback when all filename characters are stripped', () => {
+    expect(sanitizeContentDispositionFilename('";\\\r\n')).toBe('download');
+  });
+});
diff --git a/packages/api/src/storage/avatar.ts b/packages/api/src/storage/avatar.ts
new file mode 100644
index 0000000000..3ab9f0fc76
--- /dev/null
+++ b/packages/api/src/storage/avatar.ts
@@ -0,0 +1,54 @@
+import { FileSources } from 'librechat-data-provider';
+
+import type { SaveBufferParams } from './types';
+
+import { AVATAR_BASE_PATH } from './constants';
+
+type AvatarConfig =
+  | {
+      fileStrategy?: string | null;
+      fileStrategies?: {
+        avatar?: string | null;
+        default?: string | null;
+      } | null;
+    }
+  | null
+  | undefined;
+
+const sharedAvatarBasePathStrategies = new Set<string>([FileSources.s3, FileSources.cloudfront]);
+
+/**
+ * Resolves the storage strategy used for avatars. `fallbackStrategy` is usually
+ * `process.env.CDN_PROVIDER`; undefined is valid and falls back to local storage.
+ */
+export function getAvatarFileStrategy(
+  appConfig: AvatarConfig,
+  fallbackStrategy?: string | null,
+): string {
+  const config: AvatarConfig =
+    appConfig?.fileStrategy || appConfig?.fileStrategies
+      ? appConfig
+      : { fileStrategy: fallbackStrategy };
+
+  if (!config?.fileStrategies) {
+    return config?.fileStrategy ?? FileSources.local;
+  }
+
+  return (
+    config.fileStrategies.avatar ??
+    config.fileStrategies.default ??
+    config.fileStrategy ??
+    FileSources.local
+  );
+}
+
+export function getAvatarSaveParams<T extends SaveBufferParams>(
+  fileStrategy: string,
+  params: T,
+): T {
+  if (!sharedAvatarBasePathStrategies.has(fileStrategy)) {
+    return params;
+  }
+
+  return { ...params, basePath: AVATAR_BASE_PATH };
+}
diff --git a/packages/api/src/storage/cloudfront/__tests__/crud.test.ts b/packages/api/src/storage/cloudfront/__tests__/crud.test.ts
index e5da63e836..163b191751 100644
--- a/packages/api/src/storage/cloudfront/__tests__/crud.test.ts
+++ b/packages/api/src/storage/cloudfront/__tests__/crud.test.ts
@@ -4,9 +4,9 @@ import type { CloudFrontFullConfig } from '~/cdn/cloudfront';
 import type { ServerRequest } from '~/types';
 
 const mockGetCloudFrontConfig = jest.fn<CloudFrontFullConfig | null, []>();
-const mockGetS3Key = jest.fn<string, [string, string, string]>();
+const mockGetS3Key = jest.fn<string, [string, string, string, string?]>();
 const mockSaveBufferToS3 = jest.fn();
-const mockSaveURLToS3 = jest.fn();
+const mockSaveURLToS3WithMetadata = jest.fn();
 const mockUploadFileToS3 = jest.fn();
 const mockDeleteFileFromS3 = jest.fn();
 const mockGetS3FileStream = jest.fn();
@@ -22,7 +22,7 @@ jest.mock('~/cdn/cloudfront', () => ({
 jest.mock('~/storage/s3/crud', () => ({
   getS3Key: mockGetS3Key,
   saveBufferToS3: mockSaveBufferToS3,
-  saveURLToS3: mockSaveURLToS3,
+  saveURLToS3WithMetadata: mockSaveURLToS3WithMetadata,
   uploadFileToS3: mockUploadFileToS3,
   deleteFileFromS3: mockDeleteFileFromS3,
   getS3FileStream: mockGetS3FileStream,
@@ -60,8 +60,10 @@ function makeConfig(overrides: Partial<CloudFrontFullConfig> = {}): CloudFrontFu
 describe('CloudFront CRUD', () => {
   beforeEach(() => {
     jest.clearAllMocks();
-    mockGetS3Key.mockImplementation(
-      (basePath, userId, fileName) => `${basePath}/${userId}/${fileName}`,
+    mockGetS3Key.mockImplementation((basePath, userId, fileName, tenantId) =>
+      tenantId
+        ? `t/${tenantId}/${basePath}/${userId}/${fileName}`
+        : `${basePath}/${userId}/${fileName}`,
     );
     mockGetCloudFrontConfig.mockReturnValue(makeConfig());
   });
@@ -84,6 +86,18 @@ describe('CloudFront CRUD', () => {
       expect(url).toBe('https://d123.cloudfront.net/documents/user1/doc.pdf');
     });
 
+    it('uses tenant-prefixed keys when tenantId is provided', async () => {
+      const { getCloudFrontURL } = await import('~/storage/cloudfront/crud');
+      const url = await getCloudFrontURL({
+        userId: 'user1',
+        fileName: 'doc.pdf',
+        basePath: 'documents',
+        tenantId: 'tenantA',
+      });
+      expect(url).toBe('https://d123.cloudfront.net/t/tenantA/documents/user1/doc.pdf');
+      expect(mockGetS3Key).toHaveBeenCalledWith('documents', 'user1', 'doc.pdf', 'tenantA');
+    });
+
     it('strips trailing slash from domain', async () => {
       mockGetCloudFrontConfig.mockReturnValue(
         makeConfig({ domain: 'https://d123.cloudfront.net/' }),
@@ -258,8 +272,14 @@ describe('CloudFront CRUD', () => {
   });
 
   describe('saveURLToCloudFront', () => {
-    it('delegates to saveURLToS3 with a urlBuilder', async () => {
-      mockSaveURLToS3.mockResolvedValue('https://d123.cloudfront.net/images/u/f.webp');
+    it('returns the saved filepath for public API compatibility', async () => {
+      const savedFile = {
+        filepath: 'https://d123.cloudfront.net/images/u/f.webp',
+        bytes: 128,
+        type: 'image/webp',
+        dimensions: {},
+      };
+      mockSaveURLToS3WithMetadata.mockResolvedValue(savedFile);
       const { saveURLToCloudFront } = await import('~/storage/cloudfront/crud');
       const result = await saveURLToCloudFront({
         userId: 'u',
@@ -267,7 +287,7 @@ describe('CloudFront CRUD', () => {
         fileName: 'f.webp',
       });
 
-      expect(mockSaveURLToS3).toHaveBeenCalledWith(
+      expect(mockSaveURLToS3WithMetadata).toHaveBeenCalledWith(
         expect.objectContaining({
           userId: 'u',
           URL: 'https://external.com/image.jpg',
@@ -275,7 +295,25 @@ describe('CloudFront CRUD', () => {
           urlBuilder: expect.any(Function),
         }),
       );
-      expect(result).toBe('https://d123.cloudfront.net/images/u/f.webp');
+      expect(result).toBe(savedFile.filepath);
+    });
+
+    it('returns metadata from the explicit metadata variant', async () => {
+      const savedFile = {
+        filepath: 'https://d123.cloudfront.net/images/u/f.webp',
+        bytes: 128,
+        type: 'image/webp',
+        dimensions: {},
+      };
+      mockSaveURLToS3WithMetadata.mockResolvedValue(savedFile);
+      const { saveURLToCloudFrontWithMetadata } = await import('~/storage/cloudfront/crud');
+      const result = await saveURLToCloudFrontWithMetadata({
+        userId: 'u',
+        URL: 'https://external.com/image.jpg',
+        fileName: 'f.webp',
+      });
+
+      expect(result).toBe(savedFile);
     });
   });
 
@@ -437,4 +475,93 @@ describe('CloudFront CRUD', () => {
       expect(result).toBe(readable);
     });
   });
+
+  describe('getCloudFrontDownloadURL', () => {
+    it('returns a signed CloudFront URL for an existing file path', async () => {
+      mockGetCloudFrontConfig.mockReturnValue(
+        makeConfig({ privateKey: 'pk-secret', keyPairId: 'K123' }),
+      );
+      mockExtractKeyFromS3Url.mockReturnValue('t/tenantA/uploads/user1/doc.pdf');
+      mockGetSignedUrl.mockReturnValue(
+        'https://d123.cloudfront.net/t/tenantA/uploads/user1/doc.pdf?Policy=abc',
+      );
+
+      const { getCloudFrontDownloadURL } = await import('~/storage/cloudfront/crud');
+      const result = await getCloudFrontDownloadURL({
+        req: { user: { id: 'user1', tenantId: 'tenantA' } } as ServerRequest,
+        file: {
+          filepath: 'https://d123.cloudfront.net/t/tenantA/uploads/user1/doc.pdf',
+        } as TFile,
+      });
+
+      expect(result).toContain('Policy=abc');
+      expect(mockExtractKeyFromS3Url).toHaveBeenCalledWith(
+        'https://d123.cloudfront.net/t/tenantA/uploads/user1/doc.pdf',
+      );
+      expect(mockGetSignedUrl).toHaveBeenCalledWith(
+        expect.objectContaining({
+          url: 'https://d123.cloudfront.net/t/tenantA/uploads/user1/doc.pdf',
+          keyPairId: 'K123',
+          privateKey: 'pk-secret',
+        }),
+      );
+    });
+
+    it('includes response header overrides before signing download URLs', async () => {
+      mockGetCloudFrontConfig.mockReturnValue(
+        makeConfig({ privateKey: 'pk-secret', keyPairId: 'K123' }),
+      );
+      mockExtractKeyFromS3Url.mockReturnValue('uploads/user1/report.pdf');
+      mockGetSignedUrl.mockReturnValue('signed-url');
+
+      const { getCloudFrontDownloadURL } = await import('~/storage/cloudfront/crud');
+      const result = await getCloudFrontDownloadURL({
+        file: { filepath: 'https://d123.cloudfront.net/uploads/user1/report.pdf' } as TFile,
+        customFilename: 'report";\\bad.pdf',
+        contentType: 'application/pdf',
+      });
+
+      expect(result).toBe('signed-url');
+      const signedInputUrl = new URL((mockGetSignedUrl.mock.calls[0][0] as { url: string }).url);
+      expect(signedInputUrl.searchParams.get('response-content-disposition')).toBe(
+        'attachment; filename="reportbad.pdf"',
+      );
+      expect(mockGetSignedUrl).toHaveBeenCalledWith(
+        expect.objectContaining({
+          url: expect.stringContaining('response-content-disposition=attachment'),
+        }),
+      );
+      expect(mockGetSignedUrl).toHaveBeenCalledWith(
+        expect.objectContaining({
+          url: expect.stringContaining('response-content-type=application%2Fpdf'),
+        }),
+      );
+      const signingInput = mockGetSignedUrl.mock.calls[0][0] as { policy: string };
+      const policy = JSON.parse(signingInput.policy) as {
+        Statement: Array<{
+          Resource: string;
+          Condition: { DateLessThan: { 'AWS:EpochTime': number } };
+        }>;
+      };
+      expect(policy.Statement[0].Resource).toBe(
+        'https://d123.cloudfront.net/uploads/user1/report.pdf?*',
+      );
+      expect(policy.Statement[0].Condition.DateLessThan['AWS:EpochTime']).toEqual(
+        expect.any(Number),
+      );
+    });
+
+    it('throws when signing keys are missing', async () => {
+      mockGetCloudFrontConfig.mockReturnValue(makeConfig({ privateKey: null, keyPairId: null }));
+      mockExtractKeyFromS3Url.mockReturnValue('uploads/user1/doc.pdf');
+
+      const { getCloudFrontDownloadURL } = await import('~/storage/cloudfront/crud');
+      await expect(
+        getCloudFrontDownloadURL({
+          req: { user: { id: 'user1' } } as ServerRequest,
+          file: { filepath: 'https://d123.cloudfront.net/uploads/user1/doc.pdf' } as TFile,
+        }),
+      ).rejects.toThrow('Signing keys not configured');
+    });
+  });
 });
diff --git a/packages/api/src/storage/cloudfront/crud.ts b/packages/api/src/storage/cloudfront/crud.ts
index 37e41f5fa4..074ed3e5df 100644
--- a/packages/api/src/storage/cloudfront/crud.ts
+++ b/packages/api/src/storage/cloudfront/crud.ts
@@ -1,7 +1,7 @@
 import crypto from 'crypto';
-import { logger } from '@librechat/data-schemas';
 import { getSignedUrl } from '@aws-sdk/cloudfront-signer';
 import { CloudFrontClient, CreateInvalidationCommand } from '@aws-sdk/client-cloudfront';
+import { logger } from '@librechat/data-schemas';
 import type { TFile } from 'librechat-data-provider';
 import type { Readable } from 'stream';
 import type { ServerRequest } from '~/types';
@@ -10,15 +10,18 @@ import type {
   GetURLParams,
   SaveURLParams,
   UploadFileParams,
+  DownloadURLParams,
+  SaveURLResult,
   UploadResult,
 } from '~/storage/types';
 import { getCloudFrontConfig } from '~/cdn/cloudfront';
 import { s3Config } from '~/storage/s3/s3Config';
 import { DEFAULT_BASE_PATH as defaultBasePath } from '~/storage/constants';
+import { sanitizeContentDispositionFilename } from '~/storage/validation';
 import {
   getS3Key,
   saveBufferToS3,
-  saveURLToS3,
+  saveURLToS3WithMetadata,
   uploadFileToS3,
   deleteFileFromS3,
   getS3FileStream,
@@ -52,23 +55,69 @@ function buildCloudFrontUrl(s3Key: string): string {
   return `${cleanDomain}/${cleanKey}`;
 }
 
-function signUrl(url: string): string {
+function signUrl(url: string | URL): string {
   const config = getCloudFrontConfig();
   if (!config?.privateKey || !config?.keyPairId) {
     throw new Error('[signUrl] Signing keys not configured.');
   }
 
   const expiry = config.urlExpiry ?? s3Config.S3_URL_EXPIRY_SECONDS;
-  const dateLessThan = new Date(Date.now() + expiry * 1000).toISOString();
+  const expiresAtMs = Date.now() + expiry * 1000;
+  const expiresAtEpoch = Math.floor(expiresAtMs / 1000);
+
+  const urlString = url.toString();
+  const parsedUrl = url instanceof URL ? url : new URL(urlString);
+  if (parsedUrl.search) {
+    const policy = JSON.stringify({
+      Statement: [
+        {
+          Resource: `${parsedUrl.origin}${parsedUrl.pathname}?*`,
+          Condition: {
+            DateLessThan: {
+              'AWS:EpochTime': expiresAtEpoch,
+            },
+          },
+        },
+      ],
+    });
+
+    return getSignedUrl({
+      url: urlString,
+      keyPairId: config.keyPairId,
+      privateKey: config.privateKey,
+      policy,
+    });
+  }
 
   return getSignedUrl({
-    url,
+    url: urlString,
     keyPairId: config.keyPairId,
     privateKey: config.privateKey,
-    dateLessThan,
+    dateLessThan: new Date(expiresAtMs).toISOString(),
   });
 }
 
+function appendDownloadOverrides(
+  url: string,
+  customFilename: string | null,
+  contentType: string | null,
+): URL {
+  const downloadUrl = new URL(url);
+
+  if (customFilename) {
+    const safeFilename = sanitizeContentDispositionFilename(customFilename);
+    downloadUrl.searchParams.set(
+      'response-content-disposition',
+      `attachment; filename="${safeFilename}"`,
+    );
+  }
+  if (contentType) {
+    downloadUrl.searchParams.set('response-content-type', contentType);
+  }
+
+  return downloadUrl;
+}
+
 /**
  * Get CloudFront URL for a file.
  * @param sign - If true, returns a signed URL. Caller (strategy) decides based on config.
@@ -77,9 +126,10 @@ export async function getCloudFrontURL({
   userId,
   fileName,
   basePath = defaultBasePath,
+  tenantId = null,
   sign = false,
 }: CloudFrontURLParams): Promise<string> {
-  const key = getS3Key(basePath, userId, fileName);
+  const key = getS3Key(basePath, userId, fileName, tenantId);
   const url = buildCloudFrontUrl(key);
   return sign ? signUrl(url) : url;
 }
@@ -96,8 +146,19 @@ export async function saveBufferToCloudFront(
 export async function saveURLToCloudFront(
   params: SaveURLParams & { sign?: boolean },
 ): Promise<string> {
+  const { filepath } = await saveURLToCloudFrontWithMetadata(params);
+  return filepath;
+}
+
+/** Save file from URL to S3 and return CloudFront URL with fetched metadata. */
+export async function saveURLToCloudFrontWithMetadata(
+  params: SaveURLParams & { sign?: boolean },
+): Promise<SaveURLResult> {
   const { sign = false, ...rest } = params;
-  return saveURLToS3({ ...rest, urlBuilder: (p) => getCloudFrontURL({ ...p, sign }) });
+  return saveURLToS3WithMetadata({
+    ...rest,
+    urlBuilder: (p) => getCloudFrontURL({ ...p, sign }),
+  });
 }
 
 /** Upload file to S3 and return CloudFront URL. */
@@ -147,3 +208,17 @@ export async function getCloudFrontFileStream(
 ): Promise<Readable> {
   return getS3FileStream(req, filePath);
 }
+
+/** Get a signed CloudFront URL for an authorized file download. */
+export async function getCloudFrontDownloadURL({
+  file,
+  customFilename = null,
+  contentType = null,
+}: DownloadURLParams): Promise<string> {
+  const key = extractKeyFromS3Url(file.filepath);
+  if (!key) {
+    throw new Error('[getCloudFrontDownloadURL] Unable to extract S3 key from file path');
+  }
+  const url = appendDownloadOverrides(buildCloudFrontUrl(key), customFilename, contentType);
+  return signUrl(url);
+}
diff --git a/packages/api/src/storage/constants.ts b/packages/api/src/storage/constants.ts
index e6f5330aaf..c2f6ac5939 100644
--- a/packages/api/src/storage/constants.ts
+++ b/packages/api/src/storage/constants.ts
@@ -1,2 +1,5 @@
 /** Default base path for cloud-stored files (used by all storage strategies). */
 export const DEFAULT_BASE_PATH = 'images';
+
+/** Shared avatar base path for cloud-stored public/avatar assets. */
+export const AVATAR_BASE_PATH = 'avatars';
diff --git a/packages/api/src/storage/images.ts b/packages/api/src/storage/images.ts
index 479763102a..e1c770923c 100644
--- a/packages/api/src/storage/images.ts
+++ b/packages/api/src/storage/images.ts
@@ -11,7 +11,7 @@ import type {
   ImageUploadResult,
   ProcessAvatarParams,
 } from '~/storage/types';
-import { DEFAULT_BASE_PATH as defaultBasePath } from '~/storage/constants';
+import { AVATAR_BASE_PATH, DEFAULT_BASE_PATH as defaultBasePath } from '~/storage/constants';
 
 export interface ImageServiceDeps {
   resizeImageBuffer: (
@@ -97,6 +97,7 @@ export class ImageService {
         buffer: processedBuffer,
         fileName,
         basePath,
+        tenantId: req.user.tenantId ?? null,
       });
       const bytes = processedBuffer.length;
       return { filepath: downloadURL, bytes, width, height };
@@ -137,7 +138,8 @@ export class ImageService {
     userId,
     manual,
     agentId,
-    basePath = defaultBasePath,
+    basePath = AVATAR_BASE_PATH,
+    tenantId = null,
   }: ProcessAvatarParams): Promise<string> {
     try {
       const metadata = await sharp(buffer).metadata();
@@ -148,7 +150,7 @@ export class ImageService {
         ? `agent-${agentId}-avatar-${timestamp}.${extension}`
         : `avatar-${timestamp}.${extension}`;
 
-      const downloadURL = await this.saveBuffer({ userId, buffer, fileName, basePath });
+      const downloadURL = await this.saveBuffer({ userId, buffer, fileName, basePath, tenantId });
 
       const finalURL = this.config.appendManualParam
         ? `${downloadURL}?manual=${manual === 'true'}`
diff --git a/packages/api/src/storage/index.ts b/packages/api/src/storage/index.ts
index 0d2be2208a..fe545dcc01 100644
--- a/packages/api/src/storage/index.ts
+++ b/packages/api/src/storage/index.ts
@@ -2,3 +2,4 @@ export * from './cloudfront';
 export * from './s3';
 export * from './types';
 export * from './images';
+export * from './avatar';
diff --git a/packages/api/src/storage/s3/__tests__/crud.test.ts b/packages/api/src/storage/s3/__tests__/crud.test.ts
index 46e66541ec..55b5200e61 100644
--- a/packages/api/src/storage/s3/__tests__/crud.test.ts
+++ b/packages/api/src/storage/s3/__tests__/crud.test.ts
@@ -5,8 +5,11 @@ import { sdkStreamMixin } from '@smithy/util-stream';
 import { FileSources } from 'librechat-data-provider';
 import {
   S3Client,
+  UploadPartCommand,
   PutObjectCommand,
   GetObjectCommand,
+  CreateMultipartUploadCommand,
+  CompleteMultipartUploadCommand,
   HeadObjectCommand,
   DeleteObjectCommand,
 } from '@aws-sdk/client-s3';
@@ -63,6 +66,9 @@ describe('S3 CRUD', () => {
   beforeEach(() => {
     s3Mock.reset();
     s3Mock.on(PutObjectCommand).resolves({});
+    s3Mock.on(CreateMultipartUploadCommand).resolves({ UploadId: 'upload-123' });
+    s3Mock.on(UploadPartCommand).resolves({ ETag: '"part-etag"' });
+    s3Mock.on(CompleteMultipartUploadCommand).resolves({});
     s3Mock.on(DeleteObjectCommand).resolves({});
 
     const stream = new Readable();
@@ -87,12 +93,78 @@ describe('S3 CRUD', () => {
       expect(key).toBe('files/user456/folder/subfolder/doc.pdf');
     });
 
+    it('constructs tenant-prefixed keys when tenantId is provided', async () => {
+      const { getS3Key } = await import('../crud');
+      const key = getS3Key('images', 'user123', 'file.png', 'tenantA');
+      expect(key).toBe('t/tenantA/images/user123/file.png');
+    });
+
     it('throws if basePath contains a slash', async () => {
       const { getS3Key } = await import('../crud');
       expect(() => getS3Key('a/b', 'user123', 'file.png')).toThrow(
         '[getS3Key] basePath must not contain slashes: "a/b"',
       );
     });
+
+    it('throws if tenantId contains path traversal characters', async () => {
+      const { getS3Key } = await import('../crud');
+      expect(() => getS3Key('images', 'user123', 'file.png', '../tenantB')).toThrow(
+        '[getS3Key] tenantId must not contain slashes: "../tenantB"',
+      );
+    });
+
+    it('throws if userId contains path traversal characters', async () => {
+      const { getS3Key } = await import('../crud');
+      expect(() => getS3Key('images', 'user/123', 'file.png')).toThrow(
+        '[getS3Key] userId must not contain slashes: "user/123"',
+      );
+    });
+
+    it('throws if fileName contains traversal or unsafe path characters', async () => {
+      const { getS3Key } = await import('../crud');
+      expect(() => getS3Key('images', 'user123', '../file.png')).toThrow(
+        '[getS3Key] fileName must not contain path traversal: "../file.png"',
+      );
+      expect(() => getS3Key('images', 'user123', 'folder//file.png')).toThrow(
+        '[getS3Key] fileName must not contain empty path components',
+      );
+      expect(() => getS3Key('images', 'user123', 'file\u0000.png')).toThrow(
+        '[getS3Key] fileName contains unsafe path characters',
+      );
+    });
+  });
+
+  describe('parseS3Key', () => {
+    it('parses legacy keys', async () => {
+      const { parseS3Key } = await import('../crud');
+      expect(parseS3Key('images/user123/folder/file.png')).toEqual({
+        basePath: 'images',
+        userId: 'user123',
+        fileName: 'folder/file.png',
+      });
+    });
+
+    it('parses tenant-prefixed keys', async () => {
+      const { parseS3Key } = await import('../crud');
+      expect(parseS3Key('t/tenantA/images/user123/file.png')).toEqual({
+        tenantId: 'tenantA',
+        basePath: 'images',
+        userId: 'user123',
+        fileName: 'file.png',
+      });
+    });
+
+    it('returns null for incomplete keys', async () => {
+      const { parseS3Key } = await import('../crud');
+      expect(parseS3Key('images/user123')).toBeNull();
+      expect(parseS3Key('t/tenantA/images/user123')).toBeNull();
+    });
+
+    it('returns null for unsafe tenant or user segments', async () => {
+      const { parseS3Key } = await import('../crud');
+      expect(parseS3Key('t/../images/user123/file.png')).toBeNull();
+      expect(parseS3Key('images/../file.png')).toBeNull();
+    });
   });
 
   describe('saveBufferToS3', () => {
@@ -125,6 +197,28 @@ describe('S3 CRUD', () => {
       });
     });
 
+    it('uses tenant-prefixed key and URL params when tenantId is provided', async () => {
+      const urlBuilder = jest.fn().mockResolvedValue('https://cdn.example.com/t/tenantA/file.txt');
+      const { saveBufferToS3 } = await import('../crud');
+      await saveBufferToS3({
+        userId: 'user123',
+        buffer: Buffer.from('test content'),
+        fileName: 'document.pdf',
+        basePath: 'documents',
+        tenantId: 'tenantA',
+        urlBuilder,
+      });
+
+      const calls = s3Mock.commandCalls(PutObjectCommand);
+      expect(calls[0].args[0].input.Key).toBe('t/tenantA/documents/user123/document.pdf');
+      expect(urlBuilder).toHaveBeenCalledWith({
+        userId: 'user123',
+        fileName: 'document.pdf',
+        basePath: 'documents',
+        tenantId: 'tenantA',
+      });
+    });
+
     it('uses default basePath if not provided', async () => {
       const { saveBufferToS3 } = await import('../crud');
       await saveBufferToS3({
@@ -227,11 +321,18 @@ describe('S3 CRUD', () => {
     beforeEach(() => {
       global.fetch = jest.fn().mockResolvedValue({
         ok: true,
+        headers: {
+          get: (name: string) =>
+            ({
+              'content-length': '8',
+              'content-type': 'image/jpeg',
+            })[name.toLowerCase()] ?? null,
+        },
         arrayBuffer: jest.fn().mockResolvedValue(new ArrayBuffer(8)),
       }) as unknown as typeof fetch;
     });
 
-    it('fetches file from URL and saves to S3', async () => {
+    it('fetches file from URL and returns the saved filepath', async () => {
       const { saveURLToS3 } = await import('../crud');
       const result = await saveURLToS3({
         userId: 'user123',
@@ -241,7 +342,162 @@ describe('S3 CRUD', () => {
 
       expect(global.fetch).toHaveBeenCalledWith('https://example.com/image.jpg');
       expect(s3Mock.commandCalls(PutObjectCommand)).toHaveLength(1);
-      expect(result).toContain('signed=true');
+      expect(result).toBe('https://bucket.s3.amazonaws.com/test-key?signed=true');
+    });
+
+    it('fetches file from URL and returns metadata when requested', async () => {
+      const { saveURLToS3WithMetadata } = await import('../crud');
+      const result = await saveURLToS3WithMetadata({
+        userId: 'user123',
+        URL: 'https://example.com/image.jpg',
+        fileName: 'downloaded.jpg',
+      });
+
+      expect(global.fetch).toHaveBeenCalledWith('https://example.com/image.jpg');
+      expect(s3Mock.commandCalls(PutObjectCommand)).toHaveLength(1);
+      expect(result).toEqual({
+        filepath: 'https://bucket.s3.amazonaws.com/test-key?signed=true',
+        bytes: 8,
+        type: 'image/jpeg',
+        dimensions: {},
+      });
+    });
+
+    it('uses the downloaded buffer size instead of a stale content-length header', async () => {
+      (global.fetch as unknown as jest.Mock).mockResolvedValueOnce({
+        ok: true,
+        headers: {
+          get: (name: string) =>
+            ({
+              'content-length': '999',
+              'content-type': 'image/jpeg',
+            })[name.toLowerCase()] ?? null,
+        },
+        arrayBuffer: jest.fn().mockResolvedValue(new ArrayBuffer(8)),
+      });
+
+      const { saveURLToS3WithMetadata } = await import('../crud');
+      const result = await saveURLToS3WithMetadata({
+        userId: 'user123',
+        URL: 'https://example.com/image.jpg',
+        fileName: 'downloaded.jpg',
+      });
+
+      expect(result.bytes).toBe(8);
+    });
+
+    it('streams response bodies into S3 when fetch provides a stream', async () => {
+      const streamedBody = Buffer.from('streamed');
+      const arrayBuffer = jest.fn();
+      (global.fetch as unknown as jest.Mock).mockResolvedValueOnce({
+        ok: true,
+        headers: {
+          get: (name: string) =>
+            ({
+              'content-length': String(streamedBody.byteLength),
+              'content-type': 'image/png',
+            })[name.toLowerCase()] ?? null,
+        },
+        body: new ReadableStream<Uint8Array>({
+          start(controller) {
+            controller.enqueue(streamedBody);
+            controller.close();
+          },
+        }),
+        arrayBuffer,
+      });
+
+      const { saveURLToS3WithMetadata } = await import('../crud');
+      const result = await saveURLToS3WithMetadata({
+        userId: 'user123',
+        URL: 'https://example.com/image.jpg',
+        fileName: 'downloaded.jpg',
+      });
+
+      expect(arrayBuffer).not.toHaveBeenCalled();
+      expect(result).toMatchObject({
+        bytes: streamedBody.byteLength,
+        type: 'image/png',
+      });
+      const putInput = s3Mock.commandCalls(PutObjectCommand)[0].args[0].input;
+      expect(putInput.Body).toBeInstanceOf(Buffer);
+      expect(putInput.ContentLength).toBeUndefined();
+      expect((putInput.Body as Buffer).toString()).toBe('streamed');
+    });
+
+    it('uses multipart upload for streamed responses larger than one part', async () => {
+      const firstPart = Buffer.alloc(5 * 1024 * 1024, 'a');
+      const finalPart = Buffer.from('tail');
+      const uploadedParts: Buffer[] = [];
+      (global.fetch as unknown as jest.Mock).mockResolvedValueOnce({
+        ok: true,
+        headers: {
+          get: (name: string) =>
+            ({
+              'content-length': String(firstPart.length + finalPart.length),
+              'content-type': 'image/png',
+            })[name.toLowerCase()] ?? null,
+        },
+        body: new ReadableStream<Uint8Array>({
+          start(controller) {
+            controller.enqueue(firstPart);
+            controller.enqueue(finalPart);
+            controller.close();
+          },
+        }),
+        arrayBuffer: jest.fn(),
+      });
+      s3Mock.on(UploadPartCommand).callsFake(async (input) => {
+        uploadedParts.push(input.Body as Buffer);
+        return { ETag: `"part-${input.PartNumber}"` };
+      });
+
+      const { saveURLToS3WithMetadata } = await import('../crud');
+      const result = await saveURLToS3WithMetadata({
+        userId: 'user123',
+        URL: 'https://example.com/image.jpg',
+        fileName: 'downloaded.jpg',
+      });
+
+      expect(result.bytes).toBe(firstPart.length + finalPart.length);
+      expect(s3Mock.commandCalls(PutObjectCommand)).toHaveLength(0);
+      expect(s3Mock.commandCalls(CreateMultipartUploadCommand)).toHaveLength(1);
+      expect(s3Mock.commandCalls(UploadPartCommand)).toHaveLength(2);
+      expect(s3Mock.commandCalls(CompleteMultipartUploadCommand)).toHaveLength(1);
+      expect(uploadedParts[0]).toEqual(firstPart);
+      expect(uploadedParts[1]).toEqual(finalPart);
+    });
+
+    it('does not trust remote ContentLength for streamed uploads', async () => {
+      (global.fetch as unknown as jest.Mock).mockResolvedValueOnce({
+        ok: true,
+        headers: {
+          get: (name: string) =>
+            ({
+              'content-length': '4',
+              'content-type': 'image/png',
+            })[name.toLowerCase()] ?? null,
+        },
+        body: new ReadableStream<Uint8Array>({
+          start(controller) {
+            controller.enqueue(Buffer.from('decoded'));
+            controller.close();
+          },
+        }),
+        arrayBuffer: jest.fn(),
+      });
+
+      const { saveURLToS3WithMetadata } = await import('../crud');
+      const result = await saveURLToS3WithMetadata({
+        userId: 'user123',
+        URL: 'https://example.com/image.jpg',
+        fileName: 'downloaded.jpg',
+      });
+
+      expect(result.bytes).toBe(Buffer.byteLength('decoded'));
+      const putInput = s3Mock.commandCalls(PutObjectCommand)[0].args[0].input;
+      expect(putInput.ContentLength).toBeUndefined();
+      expect(putInput.Body).toEqual(Buffer.from('decoded'));
     });
 
     it('throws error on non-ok response', async () => {
@@ -285,6 +541,7 @@ describe('S3 CRUD', () => {
       const mockFile = {
         filepath: 'https://bucket.s3.amazonaws.com/images/user123/file.jpg',
         file_id: 'file123',
+        user: 'user123',
       } as TFile;
 
       s3Mock.on(HeadObjectCommand).resolvesOnce({});
@@ -297,10 +554,28 @@ describe('S3 CRUD', () => {
       expect(s3Mock.commandCalls(DeleteObjectCommand)).toHaveLength(1);
     });
 
+    it('uses the file owner for RAG cleanup when a different authorized user deletes', async () => {
+      const requesterReq = { user: { id: 'sharedUser' } } as ServerRequest;
+      const mockFile = {
+        filepath: 'https://bucket.s3.amazonaws.com/images/user123/file.jpg',
+        file_id: 'file123',
+        user: 'user123',
+      } as TFile;
+
+      s3Mock.on(HeadObjectCommand).resolvesOnce({});
+
+      const { deleteFileFromS3 } = await import('../crud');
+      await deleteFileFromS3(requesterReq, mockFile);
+
+      expect(deleteRagFile).toHaveBeenCalledWith({ userId: 'user123', file: mockFile });
+      expect(s3Mock.commandCalls(DeleteObjectCommand)).toHaveLength(1);
+    });
+
     it('handles file not found gracefully and cleans up RAG', async () => {
       const mockFile = {
         filepath: 'https://bucket.s3.amazonaws.com/images/user123/nonexistent.jpg',
         file_id: 'file123',
+        user: 'user123',
       } as TFile;
 
       s3Mock.on(HeadObjectCommand).rejects({ name: 'NotFound' });
@@ -317,17 +592,32 @@ describe('S3 CRUD', () => {
       const mockFile = {
         filepath: 'https://bucket.s3.amazonaws.com/images/different-user/file.jpg',
         file_id: 'file123',
+        user: 'user123',
       } as TFile;
 
       const { deleteFileFromS3 } = await import('../crud');
-      await expect(deleteFileFromS3(mockReq, mockFile)).rejects.toThrow('User ID mismatch');
+      await expect(deleteFileFromS3(mockReq, mockFile)).rejects.toThrow('File owner mismatch');
       expect(logger.error).toHaveBeenCalled();
     });
 
-    it('handles NoSuchKey error without calling deleteRagFile', async () => {
+    it('throws error if tenant ID does not match', async () => {
+      const mockFile = {
+        filepath: 'https://bucket.s3.amazonaws.com/t/tenantB/images/user123/file.jpg',
+        file_id: 'file123',
+        user: 'user123',
+        tenantId: 'tenantA',
+      } as TFile;
+
+      const { deleteFileFromS3 } = await import('../crud');
+      await expect(deleteFileFromS3(mockReq, mockFile)).rejects.toThrow('Tenant ID mismatch');
+      expect(logger.error).toHaveBeenCalled();
+    });
+
+    it('handles NoSuchKey error and cleans up RAG', async () => {
       const mockFile = {
         filepath: 'https://bucket.s3.amazonaws.com/images/user123/file.jpg',
         file_id: 'file123',
+        user: 'user123',
       } as TFile;
 
       s3Mock.on(HeadObjectCommand).resolvesOnce({});
@@ -336,7 +626,28 @@ describe('S3 CRUD', () => {
 
       const { deleteFileFromS3 } = await import('../crud');
       await expect(deleteFileFromS3(mockReq, mockFile)).resolves.toBeUndefined();
-      expect(deleteRagFile).not.toHaveBeenCalled();
+      expect(deleteRagFile).toHaveBeenCalledWith({ userId: 'user123', file: mockFile });
+    });
+
+    it('rejects tenant-prefixed keys when the file record lacks tenantId', async () => {
+      const mockFile = {
+        filepath: 'https://bucket.s3.amazonaws.com/t/tenantA/images/user123/file.jpg',
+        file_id: 'file123',
+        user: 'user123',
+      } as TFile;
+
+      const { deleteFileFromS3 } = await import('../crud');
+      await expect(deleteFileFromS3(mockReq, mockFile)).rejects.toThrow('Tenant ID mismatch');
+    });
+
+    it('rejects file records without an owner', async () => {
+      const mockFile = {
+        filepath: 'https://bucket.s3.amazonaws.com/images/user123/file.jpg',
+        file_id: 'file123',
+      } as TFile;
+
+      const { deleteFileFromS3 } = await import('../crud');
+      await expect(deleteFileFromS3(mockReq, mockFile)).rejects.toThrow('File record has no owner');
     });
   });
 
@@ -369,6 +680,30 @@ describe('S3 CRUD', () => {
       expect(fs.promises.unlink).not.toHaveBeenCalled();
     });
 
+    it('uses tenantId from request when uploading a file', async () => {
+      const mockReqWithTenant = {
+        user: { id: 'user123', tenantId: 'tenantA' },
+      } as ServerRequest;
+      const mockFile = {
+        path: '/tmp/upload.jpg',
+        originalname: 'photo.jpg',
+      } as Express.Multer.File;
+
+      (fs.promises.stat as jest.Mock).mockResolvedValue({ size: 1024 });
+      (fs.createReadStream as jest.Mock).mockReturnValue(new Readable());
+
+      const { uploadFileToS3 } = await import('../crud');
+      await uploadFileToS3({
+        req: mockReqWithTenant,
+        file: mockFile,
+        file_id: 'file123',
+        basePath: 'images',
+      });
+
+      const calls = s3Mock.commandCalls(PutObjectCommand);
+      expect(calls[0].args[0].input.Key).toBe('t/tenantA/images/user123/file123__photo.jpg');
+    });
+
     it('handles upload errors and cleans up temp file', async () => {
       const mockFile = {
         path: '/tmp/upload.jpg',
@@ -420,6 +755,36 @@ describe('S3 CRUD', () => {
     });
   });
 
+  describe('getS3DownloadURL', () => {
+    it('returns a signed URL for an existing file path', async () => {
+      const mockFile = {
+        filepath: 'https://bucket.s3.amazonaws.com/t/tenantA/uploads/user123/file.pdf',
+        filename: 'file.pdf',
+      } as TFile;
+
+      const { getS3DownloadURL } = await import('../crud');
+      const result = await getS3DownloadURL({
+        req: {} as ServerRequest,
+        file: mockFile,
+        customFilename: 'download";\\bad.pdf',
+        contentType: 'application/pdf',
+      });
+
+      expect(result).toContain('signed=true');
+      expect(getSignedUrl).toHaveBeenCalledWith(
+        expect.anything(),
+        expect.objectContaining({
+          input: expect.objectContaining({
+            Key: 't/tenantA/uploads/user123/file.pdf',
+            ResponseContentDisposition: 'attachment; filename="downloadbad.pdf"',
+            ResponseContentType: 'application/pdf',
+          }),
+        }),
+        expect.anything(),
+      );
+    });
+  });
+
   describe('needsRefresh', () => {
     it('returns false for non-signed URLs', async () => {
       const { needsRefresh } = await import('../crud');
@@ -469,6 +834,23 @@ describe('S3 CRUD', () => {
       expect(result).toContain('signed=true');
     });
 
+    it('generates a new URL from a tenant-prefixed S3 URL', async () => {
+      const { getNewS3URL } = await import('../crud');
+      await getNewS3URL(
+        'https://bucket.s3.amazonaws.com/t/tenantA/images/user123/file.jpg?signature=old',
+      );
+
+      expect(getSignedUrl).toHaveBeenCalledWith(
+        expect.anything(),
+        expect.objectContaining({
+          input: expect.objectContaining({
+            Key: 't/tenantA/images/user123/file.jpg',
+          }),
+        }),
+        expect.anything(),
+      );
+    });
+
     it('returns undefined for invalid URLs', async () => {
       const { getNewS3URL } = await import('../crud');
       const result = await getNewS3URL('simple-file.txt');
diff --git a/packages/api/src/storage/s3/__tests__/s3.integration.spec.ts b/packages/api/src/storage/s3/__tests__/s3.integration.spec.ts
index 5dc1e3b754..4f52ded5be 100644
--- a/packages/api/src/storage/s3/__tests__/s3.integration.spec.ts
+++ b/packages/api/src/storage/s3/__tests__/s3.integration.spec.ts
@@ -188,18 +188,19 @@ describe('S3 Integration Tests', () => {
 
   describe('saveURLToS3', () => {
     it('fetches URL content and uploads to S3', async () => {
-      const { saveURLToS3 } = await import('~/storage/s3/crud');
+      const { saveURLToS3WithMetadata } = await import('~/storage/s3/crud');
       const fileName = `url-upload-${Date.now()}.json`;
 
-      const downloadURL = await saveURLToS3({
+      const savedFile = await saveURLToS3WithMetadata({
         userId: TEST_USER_ID,
         URL: 'https://raw.githubusercontent.com/danny-avila/LibreChat/main/package.json',
         fileName,
         basePath: TEST_BASE_PATH,
       });
 
-      expect(downloadURL).toBeDefined();
-      expect(downloadURL).toContain('X-Amz-Signature');
+      expect(savedFile.filepath).toBeDefined();
+      expect(savedFile.filepath).toContain('X-Amz-Signature');
+      expect(savedFile.bytes).toBeGreaterThan(0);
     });
   });
 
diff --git a/packages/api/src/storage/s3/crud.ts b/packages/api/src/storage/s3/crud.ts
index 1ea6d32dd0..b6a1695ddc 100644
--- a/packages/api/src/storage/s3/crud.ts
+++ b/packages/api/src/storage/s3/crud.ts
@@ -1,20 +1,30 @@
 import fs from 'fs';
+import { Readable } from 'stream';
 import {
+  UploadPartCommand,
   PutObjectCommand,
   GetObjectCommand,
+  CreateMultipartUploadCommand,
+  AbortMultipartUploadCommand,
+  CompleteMultipartUploadCommand,
   HeadObjectCommand,
   DeleteObjectCommand,
 } from '@aws-sdk/client-s3';
 import { logger } from '@librechat/data-schemas';
 import { FileSources } from 'librechat-data-provider';
 import { getSignedUrl } from '@aws-sdk/s3-request-presigner';
-import type { GetObjectCommandInput } from '@aws-sdk/client-s3';
+import type {
+  CompletedPart,
+  GetObjectCommandInput,
+  PutObjectCommandInput,
+} from '@aws-sdk/client-s3';
 import type { TFile } from 'librechat-data-provider';
-import type { Readable } from 'stream';
 import type { ServerRequest } from '~/types';
 import type {
   UploadFileParams,
   SaveBufferParams,
+  DownloadURLParams,
+  SaveURLResult,
   BatchUpdateFn,
   SaveURLParams,
   GetURLParams,
@@ -22,6 +32,11 @@ import type {
   UrlBuilder,
   S3FileRef,
 } from '~/storage/types';
+import {
+  assertS3FileName,
+  assertPathSegment,
+  sanitizeContentDispositionFilename,
+} from '~/storage/validation';
 import { initializeS3 } from '~/cdn/s3';
 import { deleteRagFile } from '~/files';
 import { s3Config } from './s3Config';
@@ -35,25 +50,88 @@ const {
   DEFAULT_BASE_PATH: defaultBasePath,
 } = s3Config;
 
-export const getS3Key = (basePath: string, userId: string, fileName: string): string => {
-  if (basePath.includes('/')) {
-    throw new Error(`[getS3Key] basePath must not contain slashes: "${basePath}"`);
+const MULTIPART_UPLOAD_PART_SIZE = 5 * 1024 * 1024;
+
+export interface S3KeyParts {
+  basePath: string;
+  userId: string;
+  fileName: string;
+  tenantId?: string;
+}
+
+const parseS3PathSegment = (value: string | undefined): string | null => {
+  try {
+    return assertPathSegment('S3 key segment', value, 'getS3Key');
+  } catch {
+    return null;
   }
-  return `${basePath}/${userId}/${fileName}`;
 };
 
-export async function getS3URL({
-  userId,
-  fileName,
-  basePath = defaultBasePath,
+export const getS3Key = (
+  basePath: string,
+  userId: string,
+  fileName: string,
+  tenantId?: string | null,
+): string => {
+  const safeBasePath = assertPathSegment('basePath', basePath, 'getS3Key');
+  const safeUserId = assertPathSegment('userId', userId, 'getS3Key');
+  const safeFileName = assertS3FileName('fileName', fileName, 'getS3Key');
+
+  if (tenantId) {
+    const safeTenantId = assertPathSegment('tenantId', tenantId, 'getS3Key');
+    return `t/${safeTenantId}/${safeBasePath}/${safeUserId}/${safeFileName}`;
+  }
+  return `${safeBasePath}/${safeUserId}/${safeFileName}`;
+};
+
+export const parseS3Key = (key: string): S3KeyParts | null => {
+  const normalizedKey = key.replace(/^\/+/, '');
+  const keyParts = normalizedKey.split('/');
+
+  if (keyParts[0] === 't') {
+    if (keyParts.length < 5) {
+      return null;
+    }
+    const [, tenantId, basePath, userId, ...fileNameParts] = keyParts;
+    const safeTenantId = parseS3PathSegment(tenantId);
+    const safeBasePath = parseS3PathSegment(basePath);
+    const safeUserId = parseS3PathSegment(userId);
+    if (!safeTenantId || !safeBasePath || !safeUserId) {
+      return null;
+    }
+    return {
+      tenantId: safeTenantId,
+      basePath: safeBasePath,
+      userId: safeUserId,
+      fileName: fileNameParts.join('/'),
+    };
+  }
+
+  if (keyParts.length < 3) {
+    return null;
+  }
+  const [basePath, userId, ...fileNameParts] = keyParts;
+  const safeBasePath = parseS3PathSegment(basePath);
+  const safeUserId = parseS3PathSegment(userId);
+  if (!safeBasePath || !safeUserId) {
+    return null;
+  }
+  return { basePath: safeBasePath, userId: safeUserId, fileName: fileNameParts.join('/') };
+};
+
+async function getS3URLForKey({
+  key,
   customFilename = null,
   contentType = null,
-}: GetURLParams): Promise<string> {
-  const key = getS3Key(basePath, userId, fileName);
+}: {
+  key: string;
+  customFilename?: string | null;
+  contentType?: string | null;
+}): Promise<string> {
   const params: GetObjectCommandInput = { Bucket: bucketName, Key: key };
 
   if (customFilename) {
-    const safeFilename = customFilename.replace(/["\r\n]/g, '');
+    const safeFilename = sanitizeContentDispositionFilename(customFilename);
     params.ResponseContentDisposition = `attachment; filename="${safeFilename}"`;
   }
   if (contentType) {
@@ -73,14 +151,27 @@ export async function getS3URL({
   }
 }
 
+export async function getS3URL({
+  userId,
+  fileName,
+  basePath = defaultBasePath,
+  customFilename = null,
+  contentType = null,
+  tenantId = null,
+}: GetURLParams): Promise<string> {
+  const key = getS3Key(basePath, userId, fileName, tenantId);
+  return getS3URLForKey({ key, customFilename, contentType });
+}
+
 export async function saveBufferToS3({
   userId,
   buffer,
   fileName,
   basePath = defaultBasePath,
+  tenantId = null,
   urlBuilder,
 }: SaveBufferParams & { urlBuilder?: UrlBuilder }): Promise<string> {
-  const key = getS3Key(basePath, userId, fileName);
+  const key = getS3Key(basePath, userId, fileName, tenantId);
   const params = { Bucket: bucketName, Key: key, Body: buffer };
 
   try {
@@ -91,34 +182,212 @@ export async function saveBufferToS3({
 
     await s3.send(new PutObjectCommand(params));
     const getUrl = urlBuilder ?? getS3URL;
-    return await getUrl({ userId, fileName, basePath });
+    return await getUrl({ userId, fileName, basePath, tenantId });
   } catch (error) {
     logger.error('[saveBufferToS3] Error uploading buffer to S3:', (error as Error).message);
     throw error;
   }
 }
 
-export async function saveURLToS3({
+interface PendingUploadBuffers {
+  buffers: Buffer[];
+  bytes: number;
+}
+
+const toUploadBuffer = (chunk: Buffer | string | Uint8Array): Buffer => {
+  if (Buffer.isBuffer(chunk)) {
+    return chunk;
+  }
+  return Buffer.from(chunk);
+};
+
+const takePendingBytes = (pending: PendingUploadBuffers, size: number): Buffer => {
+  const output = Buffer.allocUnsafe(size);
+  let offset = 0;
+
+  while (offset < size) {
+    const buffer = pending.buffers[0];
+    const bytesNeeded = size - offset;
+
+    if (buffer.length <= bytesNeeded) {
+      buffer.copy(output, offset);
+      offset += buffer.length;
+      pending.bytes -= buffer.length;
+      pending.buffers.shift();
+      continue;
+    }
+
+    buffer.copy(output, offset, 0, bytesNeeded);
+    pending.buffers[0] = buffer.subarray(bytesNeeded);
+    pending.bytes -= bytesNeeded;
+    offset += bytesNeeded;
+  }
+
+  return output;
+};
+
+async function saveReadableToS3({
+  userId,
+  body,
+  fileName,
+  basePath = defaultBasePath,
+  tenantId = null,
+  urlBuilder,
+}: Omit<SaveBufferParams, 'buffer'> & {
+  body: Readable;
+  urlBuilder?: UrlBuilder;
+}): Promise<{ filepath: string; bytes: number }> {
+  const key = getS3Key(basePath, userId, fileName, tenantId);
+  const pending: PendingUploadBuffers = { buffers: [], bytes: 0 };
+  const completedParts: CompletedPart[] = [];
+  let totalBytes = 0;
+  let partNumber = 1;
+  let uploadId: string | undefined;
+
+  try {
+    const s3 = initializeS3();
+    if (!s3) {
+      throw new Error('[saveReadableToS3] S3 not initialized');
+    }
+
+    const createMultipartUpload = async (): Promise<string> => {
+      if (uploadId) {
+        return uploadId;
+      }
+      const response = await s3.send(
+        new CreateMultipartUploadCommand({ Bucket: bucketName, Key: key }),
+      );
+      if (!response.UploadId) {
+        throw new Error('[saveReadableToS3] S3 did not return an upload ID');
+      }
+      uploadId = response.UploadId;
+      return uploadId;
+    };
+
+    const uploadPart = async (partBody: Buffer): Promise<void> => {
+      const currentUploadId = await createMultipartUpload();
+      const response = await s3.send(
+        new UploadPartCommand({
+          Bucket: bucketName,
+          Key: key,
+          UploadId: currentUploadId,
+          PartNumber: partNumber,
+          Body: partBody,
+        }),
+      );
+      completedParts.push({ ETag: response.ETag, PartNumber: partNumber });
+      partNumber += 1;
+    };
+
+    for await (const chunk of body as AsyncIterable<Buffer | string | Uint8Array>) {
+      const buffer = toUploadBuffer(chunk);
+      pending.buffers.push(buffer);
+      pending.bytes += buffer.length;
+      totalBytes += buffer.length;
+
+      while (pending.bytes >= MULTIPART_UPLOAD_PART_SIZE) {
+        await uploadPart(takePendingBytes(pending, MULTIPART_UPLOAD_PART_SIZE));
+      }
+    }
+
+    if (!uploadId) {
+      const bodyBuffer =
+        pending.bytes > 0 ? takePendingBytes(pending, pending.bytes) : Buffer.alloc(0);
+      const params: PutObjectCommandInput = { Bucket: bucketName, Key: key, Body: bodyBuffer };
+      await s3.send(new PutObjectCommand(params));
+    } else {
+      if (pending.bytes > 0) {
+        await uploadPart(takePendingBytes(pending, pending.bytes));
+      }
+      await s3.send(
+        new CompleteMultipartUploadCommand({
+          Bucket: bucketName,
+          Key: key,
+          UploadId: uploadId,
+          MultipartUpload: { Parts: completedParts },
+        }),
+      );
+    }
+
+    const getUrl = urlBuilder ?? getS3URL;
+    return { filepath: await getUrl({ userId, fileName, basePath, tenantId }), bytes: totalBytes };
+  } catch (error) {
+    if (uploadId) {
+      try {
+        await initializeS3()?.send(
+          new AbortMultipartUploadCommand({ Bucket: bucketName, Key: key, UploadId: uploadId }),
+        );
+      } catch (abortError) {
+        logger.warn('[saveReadableToS3] Error aborting multipart upload:', abortError);
+      }
+    }
+    logger.error('[saveReadableToS3] Error uploading stream to S3:', (error as Error).message);
+    throw error;
+  }
+}
+
+export async function saveURLToS3WithMetadata({
   userId,
   URL,
   fileName,
   basePath = defaultBasePath,
+  tenantId = null,
   urlBuilder,
-}: SaveURLParams & { urlBuilder?: UrlBuilder }): Promise<string> {
+}: SaveURLParams & { urlBuilder?: UrlBuilder }): Promise<SaveURLResult> {
   try {
     const response = await fetch(URL);
     if (!response.ok) {
       throw new Error(`Failed to fetch URL: ${response.status} ${response.statusText}`);
     }
-    const arrayBuffer = await response.arrayBuffer();
-    const buffer = Buffer.from(arrayBuffer);
-    return await saveBufferToS3({ userId, buffer, fileName, basePath, urlBuilder });
+    const contentType = response.headers.get('content-type') ?? '';
+    if (response.body) {
+      const source = Readable.fromWeb(
+        response.body as unknown as Parameters<typeof Readable.fromWeb>[0],
+      );
+      const result = await saveReadableToS3({
+        userId,
+        body: source,
+        fileName,
+        basePath,
+        tenantId,
+        urlBuilder,
+      });
+      return {
+        filepath: result.filepath,
+        bytes: result.bytes,
+        type: contentType,
+        dimensions: {},
+      };
+    }
+
+    const buffer = Buffer.from(await response.arrayBuffer());
+    const filepath = await saveBufferToS3({
+      userId,
+      buffer,
+      fileName,
+      basePath,
+      tenantId,
+      urlBuilder,
+    });
+    return {
+      filepath,
+      bytes: buffer.byteLength,
+      type: contentType,
+      dimensions: {},
+    };
   } catch (error) {
     logger.error('[saveURLToS3] Error uploading file from URL to S3:', (error as Error).message);
     throw error;
   }
 }
 
+export async function saveURLToS3(
+  params: SaveURLParams & { urlBuilder?: UrlBuilder },
+): Promise<string> {
+  const { filepath } = await saveURLToS3WithMetadata(params);
+  return filepath;
+}
+
 export function extractKeyFromS3Url(fileUrlOrKey: string): string {
   if (!fileUrlOrKey) {
     throw new Error('Invalid input: URL or key is empty');
@@ -201,12 +470,24 @@ export async function deleteFileFromS3(req: ServerRequest, file: TFile): Promise
     throw new Error('[deleteFileFromS3] User not authenticated');
   }
 
-  const userId = req.user.id;
   const key = extractKeyFromS3Url(file.filepath);
+  const parsedKey = parseS3Key(key);
+  const ownerId = file.user?.toString?.();
+  const fileTenantId = file.tenantId?.toString?.() ?? null;
 
-  const keyParts = key.split('/');
-  if (keyParts.length < 2 || keyParts[1] !== userId) {
-    const message = `[deleteFileFromS3] User ID mismatch: ${userId} vs ${key}`;
+  if (!ownerId) {
+    const message = `[deleteFileFromS3] File record has no owner: ${key}`;
+    logger.error(message);
+    throw new Error(message);
+  }
+
+  if (!parsedKey || parsedKey.userId !== ownerId) {
+    const message = `[deleteFileFromS3] File owner mismatch: ${ownerId} vs ${key}`;
+    logger.error(message);
+    throw new Error(message);
+  }
+  if ((parsedKey.tenantId ?? null) !== fileTenantId) {
+    const message = `[deleteFileFromS3] Tenant ID mismatch: ${fileTenantId} vs ${key}`;
     logger.error(message);
     throw new Error(message);
   }
@@ -226,20 +507,21 @@ export async function deleteFileFromS3(req: ServerRequest, file: TFile): Promise
     } catch (headErr) {
       if ((headErr as { name?: string }).name === 'NotFound') {
         logger.warn(`[deleteFileFromS3] File does not exist: ${key}`);
-        await deleteRagFile({ userId, file });
+        await deleteRagFile({ userId: ownerId, file });
         return;
       }
       throw headErr;
     }
 
     await s3.send(new DeleteObjectCommand(params));
-    await deleteRagFile({ userId, file });
+    await deleteRagFile({ userId: ownerId, file });
     logger.debug('[deleteFileFromS3] S3 File deletion completed');
   } catch (error) {
     logger.error(`[deleteFileFromS3] Error deleting file from S3: ${(error as Error).message}`);
     logger.error((error as Error).stack);
 
     if ((error as { name?: string }).name === 'NoSuchKey') {
+      await deleteRagFile({ userId: ownerId, file });
       return;
     }
     throw error;
@@ -251,6 +533,7 @@ export async function uploadFileToS3({
   file,
   file_id,
   basePath = defaultBasePath,
+  tenantId = null,
   urlBuilder,
 }: UploadFileParams & { urlBuilder?: UrlBuilder }): Promise<UploadResult> {
   if (!req.user) {
@@ -260,8 +543,9 @@ export async function uploadFileToS3({
   try {
     const inputFilePath = file.path;
     const userId = req.user.id;
+    const resolvedTenantId = tenantId ?? req.user.tenantId ?? null;
     const fileName = `${file_id}__${file.originalname}`;
-    const key = getS3Key(basePath, userId, fileName);
+    const key = getS3Key(basePath, userId, fileName, resolvedTenantId);
 
     const stats = await fs.promises.stat(inputFilePath);
     const bytes = stats.size;
@@ -280,7 +564,7 @@ export async function uploadFileToS3({
 
     await s3.send(new PutObjectCommand(uploadParams));
     const getUrl = urlBuilder ?? getS3URL;
-    const fileURL = await getUrl({ userId, fileName, basePath });
+    const fileURL = await getUrl({ userId, fileName, basePath, tenantId: resolvedTenantId });
     // NOTE: temp file is intentionally NOT deleted on the success path.
     // The caller (processAgentFileUpload) reads file.path after this returns
     // to stream the file to the RAG vector embedding service (POST /embed).
@@ -320,6 +604,18 @@ export async function getS3FileStream(_req: ServerRequest, filePath: string): Pr
   }
 }
 
+export async function getS3DownloadURL({
+  file,
+  customFilename = null,
+  contentType = null,
+}: DownloadURLParams): Promise<string> {
+  const key = extractKeyFromS3Url(file.filepath);
+  if (!key) {
+    throw new Error('[getS3DownloadURL] Unable to extract S3 key from file path');
+  }
+  return getS3URLForKey({ key, customFilename, contentType });
+}
+
 export function needsRefresh(signedUrl: string, bufferSeconds: number): boolean {
   try {
     const url = new URL(signedUrl);
@@ -366,16 +662,12 @@ export async function getNewS3URL(currentURL: string): Promise<string | undefine
       return;
     }
 
-    const keyParts = s3Key.split('/');
-    if (keyParts.length < 3) {
+    const parsedKey = parseS3Key(s3Key);
+    if (!parsedKey) {
       return;
     }
 
-    const basePath = keyParts[0];
-    const userId = keyParts[1];
-    const fileName = keyParts.slice(2).join('/');
-
-    return getS3URL({ userId, fileName, basePath });
+    return getS3URL(parsedKey);
   } catch (error) {
     logger.error('Error getting new S3 URL:', error);
   }
@@ -446,17 +738,13 @@ export async function refreshS3Url(fileObj: S3FileRef, bufferSeconds = 3600): Pr
       return fileObj.filepath;
     }
 
-    const keyParts = s3Key.split('/');
-    if (keyParts.length < 3) {
+    const parsedKey = parseS3Key(s3Key);
+    if (!parsedKey) {
       logger.warn(`Invalid S3 key format: ${s3Key}`);
       return fileObj.filepath;
     }
 
-    const basePath = keyParts[0];
-    const userId = keyParts[1];
-    const fileName = keyParts.slice(2).join('/');
-
-    const newUrl = await getS3URL({ userId, fileName, basePath });
+    const newUrl = await getS3URL(parsedKey);
     logger.debug(`Refreshed S3 URL for key: ${s3Key}`);
     return newUrl;
   } catch (error) {
diff --git a/packages/api/src/storage/types.ts b/packages/api/src/storage/types.ts
index 2a5380dec2..6462b3f4bd 100644
--- a/packages/api/src/storage/types.ts
+++ b/packages/api/src/storage/types.ts
@@ -1,3 +1,4 @@
+import type { TFile } from 'librechat-data-provider';
 import type { ServerRequest } from '~/types';
 
 export interface SaveBufferParams {
@@ -5,6 +6,7 @@ export interface SaveBufferParams {
   buffer: Buffer;
   fileName: string;
   basePath?: string;
+  tenantId?: string | null;
 }
 
 export interface GetURLParams {
@@ -13,6 +15,7 @@ export interface GetURLParams {
   basePath?: string;
   customFilename?: string | null;
   contentType?: string | null;
+  tenantId?: string | null;
 }
 
 export interface SaveURLParams {
@@ -20,6 +23,17 @@ export interface SaveURLParams {
   URL: string;
   fileName: string;
   basePath?: string;
+  tenantId?: string | null;
+}
+
+export interface SaveURLResult {
+  filepath: string;
+  bytes?: number;
+  type?: string;
+  dimensions?: {
+    width?: number;
+    height?: number;
+  };
 }
 
 export interface UploadFileParams {
@@ -27,6 +41,14 @@ export interface UploadFileParams {
   file: Express.Multer.File;
   file_id: string;
   basePath?: string;
+  tenantId?: string | null;
+}
+
+export interface DownloadURLParams {
+  req?: ServerRequest;
+  file: TFile;
+  customFilename?: string | null;
+  contentType?: string | null;
 }
 
 export interface UploadImageParams extends UploadFileParams {
@@ -50,6 +72,7 @@ export interface ProcessAvatarParams {
   manual: string;
   agentId?: string;
   basePath?: string;
+  tenantId?: string | null;
 }
 
 export interface S3FileRef {
diff --git a/packages/api/src/storage/validation.ts b/packages/api/src/storage/validation.ts
new file mode 100644
index 0000000000..962f4eb89f
--- /dev/null
+++ b/packages/api/src/storage/validation.ts
@@ -0,0 +1,76 @@
+export function assertPathSegment(
+  label: string,
+  value: string | null | undefined,
+  errorPrefix = 'path segment',
+): string {
+  const segment = value?.toString?.() ?? '';
+
+  if (!segment) {
+    throw new Error(`[${errorPrefix}] ${label} must not be empty`);
+  }
+  if (segment.includes('/') || segment.includes('\\')) {
+    throw new Error(`[${errorPrefix}] ${label} must not contain slashes: "${segment}"`);
+  }
+  if (segment === '.' || segment === '..') {
+    throw new Error(`[${errorPrefix}] ${label} must not contain path traversal: "${segment}"`);
+  }
+  for (let i = 0; i < segment.length; i++) {
+    const code = segment.charCodeAt(i);
+    if (code <= 31 || code === 127) {
+      throw new Error(`[${errorPrefix}] ${label} contains unsafe path characters: "${segment}"`);
+    }
+  }
+
+  return segment;
+}
+
+export function assertS3FileName(
+  label: string,
+  value: string | null | undefined,
+  errorPrefix = 'S3 key',
+): string {
+  const fileName = value?.toString?.() ?? '';
+
+  if (!fileName) {
+    throw new Error(`[${errorPrefix}] ${label} must not be empty`);
+  }
+  if (fileName.includes('\\')) {
+    throw new Error(`[${errorPrefix}] ${label} must not contain backslashes: "${fileName}"`);
+  }
+  for (let i = 0; i < fileName.length; i++) {
+    const code = fileName.charCodeAt(i);
+    if (code <= 31 || code === 127) {
+      throw new Error(`[${errorPrefix}] ${label} contains unsafe path characters: "${fileName}"`);
+    }
+  }
+
+  const components = fileName.split('/');
+  for (const component of components) {
+    if (!component) {
+      throw new Error(`[${errorPrefix}] ${label} must not contain empty path components`);
+    }
+    if (component === '.' || component === '..') {
+      throw new Error(`[${errorPrefix}] ${label} must not contain path traversal: "${fileName}"`);
+    }
+  }
+
+  return fileName;
+}
+
+export function sanitizeContentDispositionFilename(filename: string): string {
+  let sanitized = '';
+  for (const character of filename) {
+    const code = character.charCodeAt(0);
+    if (
+      character === '"' ||
+      character === '\\' ||
+      character === ';' ||
+      code <= 31 ||
+      code === 127
+    ) {
+      continue;
+    }
+    sanitized += character;
+  }
+  return sanitized || 'download';
+}
diff --git a/packages/api/src/types/files.ts b/packages/api/src/types/files.ts
index ada6ff024c..62df64afb0 100644
--- a/packages/api/src/types/files.ts
+++ b/packages/api/src/types/files.ts
@@ -2,6 +2,7 @@ import type { BedrockDocumentFormat } from 'librechat-data-provider';
 import type { IMongoFile } from '@librechat/data-schemas';
 import type { Readable } from 'stream';
 import type { ServerRequest } from './http';
+import type { DownloadURLParams } from '~/storage/types';
 export interface STTService {
   getInstance(): Promise<STTService>;
   getProviderSchema(req: ServerRequest): Promise<[string, object]>;
@@ -170,6 +171,12 @@ export interface ProcessedFile {
   };
 }
 
+/** Subset of storage strategy functions needed by download and delete access flows. */
 export interface StrategyFunctions {
   getDownloadStream: (req: ServerRequest, filepath: string) => Promise<Readable>;
+  getDownloadURL?: (params: DownloadURLParams) => Promise<string>;
+  deleteFile?: (
+    req: ServerRequest,
+    file: { filepath: string; user?: string; tenantId?: string | null },
+  ) => Promise<void>;
 }
diff --git a/packages/api/src/utils/files.ts b/packages/api/src/utils/files.ts
index e98797b97b..91db199562 100644
--- a/packages/api/src/utils/files.ts
+++ b/packages/api/src/utils/files.ts
@@ -14,10 +14,14 @@ const UNSAFE_UNICODE_FILENAME_PATTERN = /[^\p{L}\p{M}\p{N}\p{Emoji}\u200d._-]/gu
 const FILENAME_SEGMENT_MAX_BYTES = 255;
 
 function sanitizeFilenameSegment(segment: string): string {
-  return segment
-    .normalize('NFC')
-    .replace(/[\u0000-\u007f]/g, (char) => (ASCII_FILENAME_SAFE_PATTERN.test(char) ? char : '_'))
-    .replace(UNSAFE_UNICODE_FILENAME_PATTERN, '_');
+  const asciiSanitized = Array.from(segment.normalize('NFC'), (char) => {
+    if (char.charCodeAt(0) > 0x7f) {
+      return char;
+    }
+    return ASCII_FILENAME_SAFE_PATTERN.test(char) ? char : '_';
+  }).join('');
+
+  return asciiSanitized.replace(UNSAFE_UNICODE_FILENAME_PATTERN, '_');
 }
 
 function utf8ByteLength(value: string): number {
diff --git a/packages/data-provider/src/data-service.ts b/packages/data-provider/src/data-service.ts
index 5c4dc8dfde..15cf7ed17d 100644
--- a/packages/data-provider/src/data-service.ts
+++ b/packages/data-provider/src/data-service.ts
@@ -697,6 +697,13 @@ export const getFileDownload = async (userId: string, file_id: string): Promise<
   });
 };
 
+export const getFileDownloadURL = async (
+  userId: string,
+  file_id: string,
+): Promise<f.FileDownloadURLResponse> => {
+  return request.get(`${endpoints.files()}/download-url/${userId}/${file_id}`);
+};
+
 export const getCodeOutputDownload = async (url: string): Promise<AxiosResponse> => {
   return request.getResponse(url, {
     responseType: 'blob',
diff --git a/packages/data-provider/src/types/files.ts b/packages/data-provider/src/types/files.ts
index c8f9621cc9..f4bd260e6e 100644
--- a/packages/data-provider/src/types/files.ts
+++ b/packages/data-provider/src/types/files.ts
@@ -99,6 +99,7 @@ export type TFile = {
   _id?: string;
   __v?: number;
   user: string;
+  tenantId?: string;
   conversationId?: string;
   message?: string;
   file_id: string;
@@ -176,6 +177,13 @@ export type AvatarUploadResponse = {
   url: string;
 };
 
+export type FileDownloadURLResponse = {
+  url: string;
+  filename: string;
+  type: string;
+  metadata: Partial<TFile>;
+};
+
 export type SpeechToTextResponse = {
   text: string;
 };
diff --git a/packages/data-schemas/src/methods/file.spec.ts b/packages/data-schemas/src/methods/file.spec.ts
index e8012feb5f..1d3efb56a2 100644
--- a/packages/data-schemas/src/methods/file.spec.ts
+++ b/packages/data-schemas/src/methods/file.spec.ts
@@ -88,6 +88,84 @@ describe('File Methods', () => {
     });
   });
 
+  describe('claimCodeFile', () => {
+    it('claims code output files independently per tenant', async () => {
+      const userId = new mongoose.Types.ObjectId().toString();
+
+      const tenantA = await fileMethods.claimCodeFile({
+        filename: 'report.csv',
+        conversationId: 'conversation-1',
+        file_id: 'file-tenant-a',
+        user: userId,
+        tenantId: 'tenant-a',
+      });
+      const tenantB = await fileMethods.claimCodeFile({
+        filename: 'report.csv',
+        conversationId: 'conversation-1',
+        file_id: 'file-tenant-b',
+        user: userId,
+        tenantId: 'tenant-b',
+      });
+      const tenantAAgain = await fileMethods.claimCodeFile({
+        filename: 'report.csv',
+        conversationId: 'conversation-1',
+        file_id: 'file-tenant-a-new',
+        user: userId,
+        tenantId: 'tenant-a',
+      });
+
+      expect(tenantA.file_id).toBe('file-tenant-a');
+      expect(tenantA.tenantId).toBe('tenant-a');
+      expect(tenantB.file_id).toBe('file-tenant-b');
+      expect(tenantB.tenantId).toBe('tenant-b');
+      expect(tenantAAgain.file_id).toBe('file-tenant-a');
+    });
+
+    it('keeps non-tenant code output claims in the legacy namespace', async () => {
+      const userId = new mongoose.Types.ObjectId().toString();
+
+      const legacy = await fileMethods.claimCodeFile({
+        filename: 'legacy.csv',
+        conversationId: 'conversation-1',
+        file_id: 'legacy-file',
+        user: userId,
+      });
+      const tenant = await fileMethods.claimCodeFile({
+        filename: 'legacy.csv',
+        conversationId: 'conversation-1',
+        file_id: 'tenant-file',
+        user: userId,
+        tenantId: 'tenant-a',
+      });
+
+      expect(legacy.file_id).toBe('legacy-file');
+      expect(legacy.tenantId).toBeNull();
+      expect(tenant.file_id).toBe('tenant-file');
+      expect(tenant.tenantId).toBe('tenant-a');
+    });
+
+    it('treats null tenantId as the legacy code output namespace', async () => {
+      const userId = new mongoose.Types.ObjectId().toString();
+
+      const legacy = await fileMethods.claimCodeFile({
+        filename: 'nullable-legacy.csv',
+        conversationId: 'conversation-1',
+        file_id: 'legacy-null-file',
+        user: userId,
+        tenantId: null,
+      });
+      const legacyAgain = await fileMethods.claimCodeFile({
+        filename: 'nullable-legacy.csv',
+        conversationId: 'conversation-1',
+        file_id: 'legacy-null-file-new',
+        user: userId,
+      });
+
+      expect(legacy.file_id).toBe('legacy-null-file');
+      expect(legacyAgain.file_id).toBe('legacy-null-file');
+    });
+  });
+
   describe('findFileById', () => {
     it('should find a file by file_id', async () => {
       const fileId = uuidv4();
diff --git a/packages/data-schemas/src/methods/file.ts b/packages/data-schemas/src/methods/file.ts
index 7393f4d78d..5ed87e002c 100644
--- a/packages/data-schemas/src/methods/file.ts
+++ b/packages/data-schemas/src/methods/file.ts
@@ -182,15 +182,21 @@ export function createFileMethods(mongoose: typeof import('mongoose')) {
     conversationId: string;
     file_id: string;
     user: string;
+    tenantId?: string | null;
   }): Promise<IMongoFile> {
     const File = mongoose.models.File as Model<IMongoFile>;
+    const tenantFilter = data.tenantId ? { tenantId: data.tenantId } : { tenantId: null };
+    const insertData = data.tenantId
+      ? { file_id: data.file_id, user: data.user, tenantId: data.tenantId }
+      : { file_id: data.file_id, user: data.user };
     const result = await File.findOneAndUpdate(
       {
         filename: data.filename,
         conversationId: data.conversationId,
         context: FileContext.execute_code,
+        ...tenantFilter,
       },
-      { $setOnInsert: { file_id: data.file_id, user: data.user } },
+      { $setOnInsert: insertData },
       { upsert: true, new: true },
     ).lean();
     if (!result) {