The most straight-forward way is to see the logs. First, run rag config --set dump_log true to enable logs. After that, run rag query command and check out .ragit/logs dir.
By running rag config --set dump_api_usage true, you can enable api usage logs. It records the token counts. Unfortunately, there's no fancy ui for the record yet.
With rag tfidf command, you can test its tfidf engine.