Start Connectivity Monitor

monitor.start is an internal handler: it is not offered in the flow editor's step picker. It exists as a lifecycle shell that starts a background monitor from an explicit, pre-assembled monitor configuration passed under the step's monitor config key. To monitor connectivity from a flow, use the Connectivity Monitor step (monitor.connectivity) instead — it builds this configuration from its form fields.

The provided configuration must include a monitor_id and a registered check_id; its targets selectors (role- or IP-based) are resolved to concrete addresses according to the configured address kind; the address family is a preference - ipv4/ipv6 pick the first candidate address of that family for role-resolved devices, falling back to the kind's normal choice when no literal matches, while explicit IP targets are used as written. The step fails when the configuration or either id is missing, the check is not registered, the address kind or family is invalid, no targets resolve, or starting the monitor raises an error. On success it reports the monitor's database id and target count as metrics and records one transport_meta evidence entry, monitor_started_<monitor id>, listing the resolved targets. It adds no chainable output keys.