Update a knowledge base document.
API key (sk_xxx) from Developer Settings. No X-Account-ID needed.
Successful Response
Document title
255URL-friendly slug (auto-generated if not provided)
255BlockNote block structure (JSON); null for folders
Rendered markdown for AI context; null for folders
Document visibility: 'private' or 'public'
Position for ordering
For folders, number of direct children (only in list/get)