externalSpec property
External dial-back description for this host. Returns null for
in-process implementations that never expose a wire transport.
Transport-binding implementations override this once start()
has wired a concrete URL / port / command pair so consumers
(Claude Code's --mcp-config, sibling hosts, debug tooling) can
reach the server without re-encoding wire details. See
host/mcp_server_spec.dart.
Implementation
@override
McpServerSpec? get externalSpec => _externalSpec;