THE MEDIA POOL'S SHAPE — bins (the pool's folders) and what sits in them. Use it to tidy a project: group the footage, the voice-over, the music and the graphics instead of leaving eighty files at the root. Bins are VIRTUAL and live in the project, not on disk. Moving an item between bins NEVER touches the file or its mediaRef, so it cannot break a clip's link or make the app ask the user to relocate anything — organise freely. actions: 'list' returns the bin tree and every item with the bin it shows in (call it first — you need the ids). 'create_bin' {name, parentBinId?}. 'rename_bin' {binId, name}. 'move_bin' {binId, toBinId} nests one bin inside another. 'delete_bin' {binId} — its children and items reparent, nothing is lost, no file is deleted. 'move_items' {itemKeys[], toBinId} moves files, timelines and motion compositions alike. Item keys: a media file's mediaRef, 'timeline:', 'motion:'. The Library root is the empty-string bin id. Bins that MIRROR a real folder (mirrorsFolder: true) can be RENAMED — a mirror is matched by the folder it tracks, not by its name — but they cannot be moved or deleted, because their place in the tree follows the folder. Move the items out instead, or make your own bins alongside.