Mintplex-Labs/anything-llm · info

Filename is required

Error message

Filename is required

What it means

Returned (HTTP 400) by GET /agent-skills/generated-files/:filename when the filename param is falsy. In practice this is nearly unreachable through Express itself — the :filename route segment cannot match an empty path — so hitting it means the request reached the handler without a real segment: a proxy rewrite that strips it, or programmatic invocation of the route with an empty string.

Solutions

1. Request /agent-skills/generated-files/<fileType>-<uuid>.<ext> with a real storage filename taken from the chat artifact link
2. Fix proxy rewrite rules so the :filename segment survives forwarding
3. Log the full incoming URL server-side to see what actually arrived when this fires

Example fix

# before: proxy strips the segment
location /agent-skills/generated-files/ { proxy_pass http://app/agent-skills/generated-files/; }

# after: preserve the full path
location /agent-skills/generated-files/ { proxy_pass http://app; }

function downloadUrl(filename) {
  if (!filename) throw new Error('storage filename required');
  return `/agent-skills/generated-files/${encodeURIComponent(filename)}`;
}

When it happens

Trigger: A reverse-proxy rewrite rule that forwards /agent-skills/generated-files/ with the trailing segment stripped; client URL concatenation bugs that drop the filename (usually caught earlier by the router as a plain 404); direct handler tests passing '' as the param.

Common situations: nginx/traefik rewrite misconfigurations; hand-built URL strings with a trailing slash and empty variable interpolation; monitoring probes hitting the bare collection path.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Invalid filename format
• Bad Request
• Bad Request
• Content must be a non-empty string
• is not a valid mode.

AI-assisted analysis of Mintplex-Labs/anything-llm@3aec848f28 (2026-08-18). Data as JSON: /api/errors/c74f81c94e01eae5. Report an issue: GitHub.

Appendix: source

Thrown at server/endpoints/agentFileServer.js:37

 * and ownership validation.
 */
function agentFileServerEndpoints(app) {
  if (!app) return;

  /**
   * Download a generated file by its storage filename.
   * Validates that the requesting user has access to the workspace
   * where the file was generated.
   */
  app.get(
    "/agent-skills/generated-files/:filename",
    [validatedRequest, flexUserRoleValid([ROLES.all])],
    async (request, response) => {
      try {
        const user = await userFromSession(request, response);
        const { filename } = request.params;
        if (!filename)
          return response.status(400).json({ error: "Filename is required" });

        // Validate filename format
        const parsed = createFilesLib.parseFilename(filename);
        if (!parsed) {
          return response
            .status(400)
            .json({ error: "Invalid filename format" });
        }

        // Find a chat or scheduled job run that references this file
        const fileSource = await findFileSource(filename, {
          user,
          isMultiUser: multiUserMode(response),
        });

        if (!fileSource) {
          return response.status(404).json({
            error: "File not found or access denied",

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