Why is veined octopus behavior considered a documented example of invertebrate tool use?

The behavior of the veined octopus (Amphioctopus marginatus) is considered a landmark example of tool use because it involves the deliberate collection and manipulation of external objects for a functional purpose.12

In 2009, biologists observed these octopuses excavating coconut half shells from the ocean floor and carrying them to use as portable shelters. By transporting these shells and assembling them for protection, the animals demonstrate a level of planning and foresight that distinguishes this action as the first documented instance of tool use by an invertebrate. This behavior highlights the significant intelligence and complex problem-solving capabilities found within the cephalopod class.12