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Restates 0098 through the pipeline: an action that declares a meter writes a usage event.

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Context

Usage drives billing and quotas, and it must not be confused with audit or analytics. The owner’s usage answers P6, U1, PP5 and the owner’s intent (mem L389–402, L789–791, 2026-10-20) fix the meter kinds, the event stream and the split between free declaration and the usage service.

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Decision

  1. Declaration (P6). An action declares a meter. The pipeline writes usage.recorded.v1 to the outbox. Usage, audit, analytics and domain events are four separate streams.
  2. Meter kinds (U1). @Meter kinds count, sum, max, last and unique, with windows. Tenants can define their own meters and an ingestion API.
  3. Free and paid split (owner intent, L402). Declaring meters and emitting usage events is free code. Aggregation and quotas run in the usage service, an OS service. Its tier is a plan entitlement (ADR 0215), not a package tier (contradiction C-35).
  4. Metering through the outbox (PP5). Usage is written with the change, so a metered action cannot commit without its usage.
  5. Rollups (U2 and U3). Rollups and hot counters are the usage service’s job.
  6. Free contracts. The contract types sit in @stackra/entitlements.

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Consequences

  • A usage record is never lost with its action, because both commit in one transaction.
  • Analytics and billing read different streams, so a change to one does not change the other.

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Enforcement

planned — the outbox test checks the same-transaction rule for usage; the meter kinds have unit tests.

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Open questions

  1. Who owns aggregation and its tier is settled by the plan entitlement, but the usage service’s quota rules are open (register D-05, the hot-limit overshoot).

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Supersedes and sources

Supersedes: none. Sources: owner usage answers P6, U1, PP5 (stackra-decisions-2026-10-19.md L389–402, L789–791, 2026-10-20). Contradiction C-35.