Inventory (and sub inventories)
From conversation about what does and what doesn't involve an exchange
If someone works on something (this work goes as input in the process), do you consider it and exchange? working on something sounds like a Service to me, eg. fixing 3 open bugs which took me 3 hours for tangible items, i guess whatever happens within a single 'Inventory' doesn't involve an Exchange step, single 'Inventory' in sense of 'owned' by same agent...