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Show HN: A Claude Code skill to analyze your chess games
Claude Code skills that turn one of your chess games into a post-mortem
you can actually read: plain-language explanations of your mistakes,
checked against Stockfish, and a narrated video of the whole game.
If the player above does not load (it needs a GitHub login), watch the mp4 directly (10 MB).
This is a real game of mine: a 15+10 rapid on lichess
(5KmlrdyT), White, Open Sicilian against a
Najdorf, around 1700. During the game I recorded myself thinking aloud, in
French, with a plain voice recorder running next to the board. After the
game I gave Claude two things: the lichess link and the mp3.
Claude transcribed the audio locally with whisper.cpp, then used the clock
times in the PGN to match each sentence to the move I was deciding at that
moment. So when the video says "at move eight you asked yourself whether
the bishop belongs on c4 or e2", that is my own question, answered with
the engine. Everything the video shows (the transcript, the Stockfish
sweep, the annotated PGN, the storyboard) is in examples/game-010/.
A Stockfish analysis gives you numbers and lines. It is not fun to read,
and often it does not tell you why: -1.8 after your move, and a 12-move
variation you would never find at the board.
I realized Claude can drive Stockfish itself. It asks the engine the
questions a human would ask ("why not the move I played?", "what if Black
simply takes?"), keeps asking until the answer makes sense, and writes it
down in human terms. And since it knows what I was thinking during the
game, it can refute my actual reasoning instead of a guessed one. After
the analysis I can keep asking my own questions about any position, and
it checks them with the engine before answering.
Probably not if you want a quick check of a blitz game. Lichess or
chess.com analysis does that in seconds.
It takes time. A full run (sweep, investigations, annotations, video)
takes around one hour of processing. Use it on games where you took the
time to think, not on every game you play.
Give it your thoughts. I strongly recommend passing your written notes
or an audio recording covering the whole game. Without them you get a good
engine explanation. With them you get a review of your reasoning:
which fears were justified, which plans were sound, which questions you
asked yourself and what the answer was.
Hallucinations. The AI can still get something wrong. Every claim is
checked against Stockfish and a verifier pass re-reads the result, so in
my experience errors are rare. If something looks off, ask Claude to
check that position with the engine.