curl --request GET \
  --url https://api.example.com/v1/voiceai/knowledge-base/rag-index-overview \
  --header 'x-api-key: <api-key>'

{
  "total_used_bytes": 123,
  "total_max_bytes": 123,
  "models": [
    {
      "used_bytes": 1,
      "model": "gemini-embedding-001"
    }
  ]
}