assertMessagesFitChat function

void assertMessagesFitChat(List<Message> messages, { required bool supportImage, required bool supportAudio, required bool supportsFunctionCalls, })

Throws if any message needs a capability the chat wasn't built with, so the engine never silently drops image/audio/tool content.

Implementation

void assertMessagesFitChat(
  List<Message> messages, {
  required bool supportImage,
  required bool supportAudio,
  required bool supportsFunctionCalls,
}) {
  for (final m in messages) {
    if (m.hasImage && !supportImage) {
      throw UnsupportedError(
        'This chat was created without image support; recreate it with a vision model.',
      );
    }
    if (m.hasAudio && !supportAudio) {
      throw UnsupportedError(
        'This chat was created without audio support; recreate it with an audio model.',
      );
    }
    if ((m.type == MessageType.toolResponse ||
            m.type == MessageType.toolCall) &&
        !supportsFunctionCalls) {
      throw UnsupportedError(
        'This chat was created without function-call support (tools were not passed to createChat).',
      );
    }
  }
}