Buildkite Agent API
Backplane consumed by the Buildkite Agent (open source, Go) to register, deregister, accept and finish jobs, upload artifacts, stream job logs, and emit metrics for cluster autoscaling. Authenticated via Agent Tokens issued per cluster. Public surface includes `/metrics` (for autoscaling) and `/stacks` (for self-hosted queue controllers). The `agent-edge.buildkite.com` host adds gRPC methods. Most other endpoints are reserved for internal agent use.