Considering that it's quite hard to actually delete a tool for various technical reasons, it would be nice to have an option to hide them in the interface. This would be especially useful for tools that were created as tests or never left the prototype stage.

That would make them not pollute the list of tools both for the hidden tool's owner, and for other users.

These tools would still make it impossible for other users to create tools with the same ID, but in that case, hidden tools could have a "fast-track" way of having their ownership transferred to the new person who wants that ID -- for example, by having the author state that they agree in advance with any such transfer of ownership when doing the hiding.