1 — The measurement record

2 — The allocation trail

3 — The custody log

4 — The retirement receipt

When an auditor asks you to defend a supply-chain reduction, the answer should be a set of documents, not a conversation.

A certificate resolves to four artifacts, each proving a different link in the chain. Together they are the whole story, exportable from the registry.

Instrument data, dates, and method from the source. This is what makes the reduction measurable — the raw evidence that a real change was quantified, not estimated from a table. It is the foundation the other three artifacts build on, because a custody trail for an unmeasured number proves nothing.

Supply-shed attribution and the mass-balance math that moved performance from origin to your specific volume. This shows the reduction is attributable to your goods and was never over-issued — the arithmetic that connects a herd or a field to your particular purchase.

Every transfer and transformation, timestamped. The chain of custody proves the link from producer to buyer is unbroken. Where the allocation trail is the math, the custody log is the timeline — who held the goods, and the attached performance, at each step.