1. 1.Stockfish plays every move, in your browser.
2. 2.It reports the eval swing and the move it wanted.
3. 3.The coach explains why that move was better.

Play a real engine. Find out why you lost.

Stockfish supplies the moves and the numbers. The coach supplies the reason — tied to the eval swing it actually measured.

The engine runs client-side. Nothing about a game against it leaves the browser until the coach is asked for an explanation. Playing a person needs an account, and no engine help is available while you do.