Mintplex-Labs/anything-llm · warning

Message is empty

Error message

Message is empty

What it means

HTTP 400 from POST /api/v1/workspace/:slug/thread/:threadSlug/chat when message is falsy/empty (!message?.length) and reset is not true. Identical guard to the workspace stream-chat endpoint: a reset request (to clear thread history) is the only sanctioned way to send an empty message. Aborts come back in the abort-shaped body.

Source

Thrown at server/endpoints/api/workspaceThread/index.js:435

        });
        if (!thread) {
          response.status(404).json({
            id: uuidv4(),
            type: "abort",
            textResponse: null,
            sources: [],
            close: true,
            error: `Thread ${threadSlug} not found.`,
          });
          return;
        }

        const resolvedMode = mode ?? workspace.chatMode;
        if (
          (!message?.length || !VALID_CHAT_MODE.includes(resolvedMode)) &&
          !reset
        ) {
          response.status(400).json({
            id: uuidv4(),
            type: "abort",
            textResponse: null,
            sources: [],
            close: true,
            error: !message?.length
              ? "Message is empty"
              : `${resolvedMode} is not a valid mode.`,
          });
          return;
        }

        const user = userId ? await User.get({ id: Number(userId) }) : null;
        const result = await ApiChatHandler.chatSync({
          workspace,
          message,
          mode: resolvedMode,
          user,

View on GitHub (pinned to 3aec848f28)

Solutions

1. Always send a non-empty message string
2. To clear thread history only, send {reset:true} with or without a message
3. Set Content-Type: application/json and verify the serialized body
4. Disable send while input is blank

Example fix

// before
if (!prompt) prompt = ' ';
// after
if (!prompt?.trim()) throw new Error('message required (or use reset:true)');

if (!message?.length && !reset) throw new Error('message required unless reset:true');

const hasMessage = (b) => typeof b?.message === 'string' && b.message.length > 0;

When it happens

Trigger: Sending {message:''} or omitting message; sending {message:null}; JSON body not parsed due to missing application/json Content-Type so message never arrives.

Common situations: Empty textarea submits; templated prompts rendering to empty string; client libraries defaulting unspecified string fields to empty rather than dropping them.

Related errors

• Query parameter cannot be empty.
• ${resolvedMode} is not a valid mode.
• Workspace ${slug} not found.
• Thread ${threadSlug} not found.
• e.message

AI-assisted analysis of Mintplex-Labs/anything-llm@3aec848f28 (2026-08-18). Data as JSON: /api/errors/690ba8449d73992c. Report an issue: GitHub.