A logistics platform should treat a provider-enforced spend cap and an application rate limiter as two different failure boundaries. The cap can stop eligible billable work only where the upstream account recognizes the cap; the limiter can slow or reject requests only where our application sees them. Neither one, by itself, can tell us which warehouse, route, or customer caused the balance to fall.

Short answer: use the upstream cap as a last-resort account boundary, and use application rate limiting as a controllable traffic boundary. Put attribution in the metering path between them: record the tenant, operation, provider account, request outcome, and chargeable quantity before aggregating.…