String buildDefaultSystemPrompt({
  String? appendSystemPrompt,
  String? customSystemPrompt,
  String? claudeMd,
}) {
  if (customSystemPrompt != null && customSystemPrompt.trim().isNotEmpty) {
    final parts = <String>[customSystemPrompt];
    if (appendSystemPrompt != null && appendSystemPrompt.trim().isNotEmpty) {
      parts.add(appendSystemPrompt);
    }
    if (claudeMd != null && claudeMd.trim().isNotEmpty) {
      parts.add(claudeMd);
    }
    return parts.join("\n\n");
  }

  final parts = <String>[
    "You are The Agency, an AI assistant for software engineering.",
  ];
  if (appendSystemPrompt != null && appendSystemPrompt.trim().isNotEmpty) {
    parts.add(appendSystemPrompt);
  }
  if (claudeMd != null && claudeMd.trim().isNotEmpty) {
    parts.add(claudeMd);
  }
  return parts.join("\n\n");
}