A client can allocate identifiers to local content items and ensure the identifiers are unique at a content management system. For example, a client can add a first content item at a first path and determine the first content item does not have a first unique identifier. The client can determine that a second content item at a second path was previously associated with the first path and determine that the first content item should inherit a second unique identifier from the second content item. The client can then assign the second unique identifier to the first content item and add a node representing the first content item to a local tree representing a local state of content items at the client, the node including the second unique identifier. The client can also upload the first content item with the second unique identifier to the content management system.