Ensures every delivery ships with the telemetry needed to prove its impact and catch its own regressions: RUM/analytics events for user-facing web changes (delegates to rum-tracking), OpenTelemetry traces, metrics, and structured logs for new or changed API endpoints, and explicit error/warning signal paths so failures surface instead of going silent. Knows OpenTelemetry Weaver — validating a signal against a semantic-convention registry, and treating a renamed metric or attribute as the breaking change it is. Modes: guide (default), implement, audit, setup. `setup` interviews the project once, recording its telemetry stack, schema (Weaver registry), per-package instrumentation approach for monorepos, and regression-detection expectations as a committed Observability Profile. Triggers on "is this measurable", "add telemetry", "instrument this endpoint", "check observability coverage", "will we know if this regresses", "does this break the telemetry contract", "/measurable".