serveModelMcp function

ModelMcpServer? serveModelMcp(List<String> arguments, { McpTools? projectTools, })

Opens the project arguments names and serves it over stdio, offering projectTools beside the modeller's own.

The registry rather than the plugins. Installing a plugin takes a plugin host, which belongs to flutter3d_sim's EngineLoop, and this package depends on no simulation. So a project that wants its plugins' tools offered installs them where it already does — a loop handed the registry among its registries — and starts the server from a bin/ of its own with that registry:

void main(List<String> arguments) {
  final tools = McpTools();
  EngineLoop(input: InputState(), registries: [tools],
      plugins: installedPlugins.plugins);
  serveModelMcp(arguments, projectTools: tools);
}

dart run flutter3d_mcp:model_mcp hands it an empty one, which lists nothing beside the modeller's tools until something is added.

--help prints the usage and returns null; a wrong argument count or a project that will not parse is written to stderr and ends the process non-zero, before the protocol starts, for the reason bin/model_mcp.dart gives.

Implementation

ModelMcpServer? serveModelMcp(
  List<String> arguments, {
  McpTools? projectTools,
}) {
  if (arguments.contains('--help') || arguments.contains('-h')) {
    stderr.writeln(modelMcpUsage);
    return null;
  }
  if (arguments.length != 1) {
    stderr.writeln(modelMcpUsage);
    // The usage code of the `flutter3d` command's contract (`CliExit.usage`
    // in flutter3d_build), so a script reads every flutter3d tool alike.
    exit(2);
  }

  final ModelSession session;
  try {
    session = ModelSession.open(arguments.first);
  } catch (error) {
    stderr.writeln('could not open ${arguments.first}: $error');
    // The failure code of the `flutter3d` command's contract
    // (`CliExit.failure`): a file it could not read.
    exit(1);
  }

  return ModelMcpServer(
    stdioChannel(input: stdin, output: stdout),
    session: session,
    projectTools: projectTools ?? McpTools(),
  );
}