643 B
643 B
ADR-0038: Versioned SLO and error-budget model
Status
Accepted in M14 on 2026-08-27.
Decision
Separate immutable SLI definitions from versioned SLO policies and immutable evaluation snapshots. Only production policies receive error budgets. Minimum population and freshness are evaluated before health; short and rolling-window burn rates remain distinct.
Consequences
Threshold changes cannot rewrite historical meaning. LAB evidence cannot masquerade as production
reliability. A serving capability can consume budget without being misreported as unavailable, and
too little evidence remains explicitly INSUFFICIENT_DATA.