It's great. I tried using it to optimize a tweet, but it generated too many emojis. So I told it not to generate too many emojis, and this time the result was quite satisfactory.
It runs in a sandbox, each session lasting ten minutes, and the session is cleared after a page refresh.
However, after using it twice, it threw an error: "Failed to initialize sandbox: HTTP 500: Please refresh the page to try again."