FACILITY/INPUT_SLOT_CHANGED
A selected input slot is empty or contains a different item.
Classification
Application code. The wire value and spelling remain the same in every language. A registered code does not establish that its feature is active in every deployment.
Handling
Keep the command-result envelope. Map recognized domain codes to the existing facility result code and show guidance in the workspace. Check confirmed input, inventory and receipt state before another mutation; a stopped sequence does not roll back completed crafts.