🤐 feat: Allow Promptless Sends When Files Are Attached (#13717)

* ✨ feat: Allow sending file attachments without a text message

When an agent asks the user to upload a document, the user could attach
the file but still had to type a placeholder message ("OK", "Here is
the file") before the send button enabled and the submit guard let the
message through.

Attachments now count as submittable content:

- New isSubmittableMessage(text, fileCount) util: non-whitespace text
  OR at least one attached file.
- ask() in useChatFunctions uses it instead of bailing on empty text,
  so an empty draft with attached files submits.
- SendButton receives the attached file count and enables accordingly.
- ChatForm only marks the text field as required when no files are
  attached, so react-hook-form validation no longer blocks handleSubmit.

Submitting an empty draft with no attachments is still rejected at all
three layers.

Fixes #13646

* Address review: support replayed file-only turns + drop empty vision text

- ask(): count replayed attachments (overrideFiles) in the submittable
  check and skip it entirely for regenerate, so a file-only message can
  be regenerated or saved-and-resubmitted instead of being rejected as
  empty.
- formatVisionMessage(): omit the text content part when the message text
  is empty. Anthropic rejects empty text content blocks with HTTP 400,
  and an empty block adds nothing for other providers; image-only sends
  now format cleanly. Added formatMessages tests for with-text and
  image-only (Anthropic + other) cases.

* Address review: keep attachment-only turns valid for providers, answer mode, and titles

- formatMessage: substitute minimal text when a user turn carries files but no
  inline content, so Anthropic does not reject an empty user message for RAG or
  code-environment attachments.
- assistants chatV1: send the same stand-in for attachment-only Threads
  messages, which reject an empty body. The persisted message keeps empty text.
- ChatForm: attachments no longer make an empty draft submittable in answer
  mode, where submitText consumes the click without answering or sending.
- agents request: seed title generation from attachment filenames when the turn
  has no text, so immediate-mode titles are not invented from an empty string.
- useChatFunctions.regenerate.spec: mock the utils barrel over the real module
  so new exports resolve.

* Cover the agents path for attachment-only turns

AgentClient formats its payload with the SDK's formatMessage, not the local
one, so the earlier guard missed the endpoint the feature actually targets: an
attachment-only turn still reached Anthropic as an empty user message. Apply
the same stand-in after the file-context and quote merges, so a turn that
already gained inline content is untouched.

* Carry filenames on freshly attached files

The fresh-file submission mapping copied only file_id, filepath, type, and
dimensions, so the attachment-only title fallback read an undefined filename
and produced nothing. Include filename, and cover it with a test that submits
an empty draft with one attachment.

* Address review: cover assistants v2, fresh agent attachments, editor, and title fallback

- agents client: the current turn has no files during buildMessages, so read
  the resolved attachments from message_file_map instead. The previous guard
  only ever fired for persisted historical turns.
- assistants chatV2: the default assistants endpoint routes here, so it needs
  the same stand-in body chatV1 got.
- assistants title: fall back to filenames, then the response, and keep the
  default title rather than saving an empty one.
- EditMessage: retained attachments make an empty edit submittable, matching
  the composer, so the overrideFiles replay path is reachable from the UI.

---------

Co-authored-by: Marco Beretta <81851188+berry-13@users.noreply.github.com>

api/server/controllers/agents/client.js

@@ -78,6 +78,7 @@ const {
   countFormattedMessageTokens,
   prependFileContext,
   prependQuotes,
+  applyAttachmentOnlyText,
   hydrateMissingIndexTokenCounts,
   injectSkillPrimes,
   collectFreshSkillPrimeNames,
@@ -1368,6 +1369,19 @@ class AgentClient extends BaseClient {
         prependQuotes(memoryFormattedMessage, message.quotes);
       }
 
+      /**
+       * An attachment-only turn whose files reach the model out-of-band (file
+       * search, code environment) leaves nothing in the content itself, and
+       * providers such as Anthropic reject an empty user message outright.
+       * Applied after the context and quote merges so a turn that already
+       * gained inline content keeps it. The current turn is not carrying
+       * `files` yet (BaseClient assigns them after this returns), so the
+       * resolved attachments come from `message_file_map`.
+       */
+      const turnFiles = this.message_file_map?.[message.messageId] ?? message.files;
+      applyAttachmentOnlyText(formattedMessage, turnFiles);
+      applyAttachmentOnlyText(memoryFormattedMessage, turnFiles);
+
       memoryPayload.push(memoryFormattedMessage);
 
       const dbTokenCount = Number(orderedMessages[i].tokenCount);

api/server/controllers/agents/request.js

@@ -25,6 +25,7 @@ const {
   isSteerPreemptSupported,
   buildRecoveredSteerPayload,
   deleteAgentCheckpoint,
+  getAttachmentTitleText,
 } = require('@librechat/api');
 const { disposeClient } = require('~/server/cleanup');
 const {
@@ -1325,7 +1326,7 @@ const ResumableAgentController = async (req, res, next, initializeClient, addTit
 
         if (titleEligible && titleTiming === 'immediate') {
           immediateTitlePromise = addTitle(req, {
-            text,
+            text: text || getAttachmentTitleText(req.body.files),
             conversationId,
             client,
             immediate: true,
@@ -1712,7 +1713,7 @@ const ResumableAgentController = async (req, res, next, initializeClient, addTit
           }
         } else if (shouldGenerateTitle) {
           addTitle(req, {
-            text,
+            text: text || getAttachmentTitleText(req.body.files),
             response: { ...response },
             client,
           })

api/server/controllers/assistants/chatV1.js

@@ -7,6 +7,7 @@ const {
   checkBalance,
   getBalanceConfig,
   getModelMaxTokens,
+  ATTACHMENT_ONLY_TEXT,
 } = require('@librechat/api');
 const {
   Time,
@@ -321,9 +322,14 @@ const chatV1 = async (req, res) => {
       parentMessageId = previousMessages[previousMessages.length - 1].messageId;
     }
 
+    /**
+     * Threads rejects an empty message body, so an attachment-only turn sends
+     * a minimal note instead. The persisted message keeps its empty text.
+     */
+    const isAttachmentOnly = !text?.trim() && files.length > 0;
     let userMessage = {
       role: 'user',
-      content: text,
+      content: isAttachmentOnly ? ATTACHMENT_ONLY_TEXT : text,
       metadata: {
         messageId: userMessageId,
       },

api/server/controllers/assistants/chatV2.js

@@ -7,6 +7,7 @@ const {
   checkBalance,
   getBalanceConfig,
   getModelMaxTokens,
+  ATTACHMENT_ONLY_TEXT,
 } = require('@librechat/api');
 const {
   Time,
@@ -194,12 +195,17 @@ const chatV2 = async (req, res) => {
       parentMessageId = previousMessages[previousMessages.length - 1].messageId;
     }
 
+    /**
+     * Threads rejects an empty message body, so an attachment-only turn sends
+     * a minimal note instead. The persisted message keeps its empty text.
+     */
+    const isAttachmentOnly = !text?.trim() && files.length > 0;
     let userMessage = {
       role: 'user',
       content: [
         {
           type: ContentTypes.TEXT,
-          text,
+          text: isAttachmentOnly ? ATTACHMENT_ONLY_TEXT : text,
         },
       ],
       metadata: {

api/server/services/Endpoints/assistants/title.js

@@ -1,4 +1,4 @@
-const { isEnabled, sanitizeTitle } = require('@librechat/api');
+const { isEnabled, sanitizeTitle, getAttachmentTitleText } = require('@librechat/api');
 const { logger } = require('@librechat/data-schemas');
 const { CacheKeys } = require('librechat-data-provider');
 const getLogStores = require('~/cache/getLogStores');
@@ -78,7 +78,18 @@ const addTitle = async (req, { text, responseText, conversationId }) => {
     );
   } catch (error) {
     logger.error('[addTitle] Error generating title:', error);
-    const fallbackTitle = text.length > 40 ? text.substring(0, 37) + '...' : text;
+    /**
+     * An attachment-only turn has no text to fall back on, and saving the
+     * empty string would replace the conversation's default title with a
+     * blank sidebar entry. Use the filenames, then the response, and leave
+     * the default in place when neither says anything.
+     */
+    const fallbackSource = text || getAttachmentTitleText(req?.body?.files) || responseText || '';
+    if (!fallbackSource) {
+      return;
+    }
+    const fallbackTitle =
+      fallbackSource.length > 40 ? fallbackSource.substring(0, 37) + '...' : fallbackSource;
     await titleCache.set(key, fallbackTitle, 120000);
     await saveConvo(
       {