--part reels:
instagram:0 is an example resource ID; use the ID in your saved result. Profile resources offer only operations supported by returned identities: posts need a handle, while reels can use the numeric user ID or handle. The resource preserves a pointer to the original provider record, which remains available in full. Following it makes a new provider request.
Direct --user-id or --handle input remains available. If a result has no usable identity, inspect the original data and the operation’s scoped help instead of inventing an ID. Provider payloads differ between operations; a profile’s nested user and a reel’s media author are not interchangeable.
A reels page may contain collaborations owned by other accounts. Check each item’s media.user.username and date before calling it the profile owner’s reel. The studied reels page returned a resource ID for a selected NASA-owned item; following it preserved the exact post target:
instagram:10 belongs to that one saved reels result. Inspect your own resources and use the corresponding ID. This is a new provider read, and the list page’s assets may still be empty. The post detail can return image or video asset descriptors. In the study, it returned both an MP4 descriptor and a JPEG asset; only the JPEG bytes were downloaded and verified. Use downloads for the returned asset ID. A reel URL or an MP4 descriptor alone does not prove that video bytes were saved.