# P3-WP12 Metering and Showback Operations

## Operating boundary

This is an `ENGINEERING_EVIDENCE_ONLY` local fixture baseline. The enterprise `cost` input is `TBD_EXTERNAL`, owned by `enterprise_finance_owner`. Do not connect billing, finance, mail, chat or collaboration systems; do not treat fixture events as an invoice, enterprise bill, UAT result, receivable, payment, deduction or settlement.

## Safe procedures

- Ingest only `local-metering-fixture-v1@1` events with the eight closed kinds. Persist safe SHA-256 evidence digest and `local-fixture://wp12/v1` reference only.
- Submit the same idempotency key and immutable event unchanged to replay; a changed digest is a conflict. A late observation is a new event with `correction_of`; never update or delete its source event.
- Use Decimal strings and integer micros only. Reject floats, booleans, NaN/Infinity, incompatible unit dimensions, Unicode-normalized/confusable identifiers, URLs, credentials, raw rows, SQL, scripts and oversized bodies.
- Read Showback and reconciliation through the gateway/API with a server-derived principal and persisted scope. The report must have `difference_micros=0` before it is described as locally reconciled.
- Explain an allocation only through the persisted `allocation-replay` gateway using its immutable `rule_uid`, `rule_version` and month. Its returned rule digest, source micros and per-target integer-micros are the local replay evidence; do not substitute a reconstructed spreadsheet or a mutable rule.
- Inspect budget alert outbox as a local disabled-provider record. It never delivers externally.

## Recovery and activation

- On worker interruption, acquire a new claim and lease. A stale lease fence must be rejected; never reuse an old fence.
- Downgrade is allowed only when all metering facts, allocations, budgets, alerts, reports, audits, claims, leases and grants are empty. The default disabled configuration row does not represent an activated cost program.
- Activation requires approved enterprise cost center/master data, metering sources, price/cost method, budgets, Showback decision, finance approval and UAT. Until then the state ceiling is `ENGINEERING_BASELINE_COMPLETE_SHOWBACK_ACTIVATION_BLOCKED`.