docs/usage/external-gateway-operations.md。本页保留英文规范正文，中文导航和摘要页已提供双语入口。External Gateway Operations（英文规范）
The root gateway/ package currently defines the provider-neutral lifecycle;
it does not yet ship an Envoy Gateway, APISIX, or Higress adapter. Operators
must not treat the foundation or a successful administrative call as a usable
data-plane route.
Rollout
A provider adapter must receive one exact RouteSpec, reject unsupported
capabilities, reconcile the desired revision, and report observed status.
accepted and programmed are not readiness. Traffic may begin only when the
adapter has explicit data_plane_readiness capability and reports its
documented evidence.
Reconciliation Failure
Keep desired and observed revisions distinct. A rejected, unavailable, unauthorized, stale, or not-ready outcome must remain visible. Do not switch providers, upstreams, Releases, discovery owners, or cached route state.
Drain And Deletion
Begin drain only when the provider advertises drain capability. Preserve existing streaming and cancellation affinity for the adapter's documented grace period, stop new traffic, observe the drained state, and then delete the exact route revision. A missing route is not equivalent to successful drain.
Backend Outage And Recovery
Provider management availability and Agent data-plane readiness are separate. During a backend outage, expose the provider's typed state and leave the exact Release and discovery owner unchanged. Recovery consists of reconciling the same desired route and observing its readiness evidence; no automatic retry, alternate endpoint, or fallback provider is permitted.