Yes, it is safe. You can verify in the network tab that your API keys are only used to make calls to the API providers and are stored locally in your browser's storage. If you still have concerns, consider using Ollama, which runs on your own computer.

The quality of the generated summary depends on the model you're using. You can research online to find the model that best suits your needs. I've found the gpt-4o-mini from OpenAI to be particularly effective for summarization.