outlook.listAttachments returns metadata for file, item, and reference attachments across all Graph pages without downloading their contents.
automations/list-outlook-attachments.automation.ts
messageId. Optional limit defaults to 100 and permits 1–10,000 across pages. Optional second argument { account } selects the binding.
Returns attachments with attachmentId, name, size, isInline, and optional MIME type. type accepts file, item, reference, or unknown. Use outlook.getAttachment when you need subtype metadata or one attachment’s contents.