countTokens method
Count tokens for messages using Anthropic's API
API Reference: https://docs.anthropic.com/en/api/messages-count-tokens
This uses Anthropic's dedicated token counting endpoint to provide accurate token counts for messages, system prompts, tools, and thinking configurations without actually sending a chat request.
Implementation
Future<int> countTokens(List<ChatMessage> messages,
{List<Tool>? tools}) async {
return _chat.countTokens(messages, tools: tools);
}