Spool Bridge

3D printer filament inventory goes stale the moment you have to update it by hand. This closes the loop: each spool carries an NFC tag pointing at its own record, and the printer reports consumption automatically as it prints.

It also has a maintenance story worth knowing about. Every official printer firmware update strips the configuration include this depends on, silently. There is now a repair script and a check for it, because the failure mode is not an error, it is inventory that quietly stops updating.