Create a nested subfolder inside an existing parent folder, named by the folderId path parameter. It runs the same validator and handler as POST /knowledgeBase/{kbId}/folder. A folderId query parameter is still read: one that names a different folder than the path is refused with 400.

Required permission: WRITER or higher

Folder features:

• Organize records hierarchically
• Support nested subfolders, up to 20 levels deep
• Inherit parent KB permissions

Naming rules:

• Whitespace around the name is removed first; then 1–255 characters
• A name holding an HTML tag, a javascript: URL or an inline event handler is refused with 400 before authentication; one holding a printf-style format specifier (%s, %x, %n, %p) is refused with 400 by the gateway controller
• Spaces and special characters allowed
• A name already used by a folder in the same parent is refused with 409, ignoring case (Reports and rEPORTS clash). A file of the same name, or a folder of the same name under another parent, does not clash.

Request: only folderName and the folderId query parameter are read; other body fields and query parameters are ignored, except a folderId, parentId or parent_id in the body and a parentId or parent_id query parameter, which are refused with 400.

Access: a caller with no role on the knowledge base gets 404 (Knowledge base <kbId> not found), a READER gets 403.

Response: Returns id and name for the created folder.

{
  "folderName": "Project Documents"
}