writeMcpSessionFile function
Where an application's own running LoopbackMcpServer can be found,
written beside the application's existing session state.
Takes the directory as a plain path rather than resolving a per-platform
application-support directory, because this package stays plain Dart and
the application wiring a server in already has that directory. Written
after the socket is bound, since port and token both come from the
running server — a file naming a port nothing is listening on yet would
race whatever reads it.
Implementation
void writeMcpSessionFile(
File file, {
required int port,
required String token,
}) {
file.parent.createSync(recursive: true);
file.writeAsStringSync(
json.encode(<String, Object?>{'port': port, 'token': token}),
);
}