Show HN: A Claude Code skill to analyze your chess games

Show HN: A Claude Code skill to analyze your chess games(github.com)

43 points by brumar 2 hours ago | 29 comments

Hello HN,

It started as an experiment: can Claude play chess properly if it uses vision instead of PGN notation? Somehow it can.

The next experiment was to see whether Claude + Stockfish could explain a game. Somehow it can too.

A few sessions later, I had a system that takes my live audio notes (or text, for that matter) and a vague instruction like "analyze my last lichess game", and gives me a commented video of the game. The result is not perfect and it takes time to deliver (an hour or so), but for me it is a much more pleasant and memorable experience than clicking around Stockfish branches. It burns tokens, so make sure you have enough quota. From the session logs, the last analyzed game would have cost around $15 at API prices.

The fact that it reflects on my own thinking during the game makes it interesting from a teaching point of view, so I thought it was worth sharing.

brausepulver 23 minutes ago |

Does this give sensible analysis if you don't record your thinking out loud?

I've been using Elogram (https://elogram.gg/, made by a friend), which gives interpretability by showing how difficulty of a position changes with elo.

dverlaeckt80 33 minutes ago |

As a chess player I feel this is fascinating although there are plenty of analysis options already on lichess on chess.com. Still, sometimes it is more about learning and curiosity. Well done.

michaelastreiko 25 minutes ago |

Nice use of a skill for something concrete. I've been happier with AI helpers that spit out a short, checkable report than ones that try to be a whole coach.

WoodenChair 1 hour ago |

Just a note that this is not novel. Automatic analysis of chess games built on traditional engines has existed for a long time. Without using stockfish as a sidekick, this wouldn’t be interesting because of the poor play of LLMs, however having an LLM enhance the commentary is interesting and I suspect has already been done by chess.com for years.

kuboble 45 minutes ago | |

I'm an ok chess player (roughly OP level) and slightly more experienced claude code user.

I tried to use claude to analyze my games using stockfish - this is not a problem claude is good at.

I spent few hours (however admittedly around opus 4.8) with claude on this and it was unable to use stockfish in any useful way.

I think if the skill created by OP works then it's a real contribution. I'll give it a try.

brumar 18 minutes ago | | |

Thanks for trying it out! I'd be happy to see how it goes for you and compare our implementation notes if the analysis you got is not too bad.

brumar 1 hour ago | |

This what I think too. I also think there are much more refined approaches than the one I tried here. From a cursory look, I saw there are both scientific litterature on the subject of mixing llms and tools like stockfish and some dedicated closed platforms that put that into action.

Let's make clear that I did not spend much time on this project. Ideally I would have tried to put other models into the mix, like maybe Maia to better see the game from a "real player" eyes and pinpoint where expected move and stockfish moves differ.

Anyway, to me, it's good enough to be usable and shared.

kokoe 1 hour ago |

You could also download my free chess app that hooks up to Claude for real time game analysis or chat about the game. https://pwalessi.itch.io/chess-buddy

Simpliplant 1 hour ago | |

Looks really cool, would love to try it but I'm on Mac so would appreciate Mac version.

brumar 1 hour ago | |

Thanks for sharing! So you gave stockfish to Claude too? Did you try other techniques?

qwend 1 hour ago |

How does it work? Does it just use stockfish under the hood? I just remember the times when I tried to use an AI model to play chess and half of the time it either hung a piece or made an illegal move.

qwend 1 hour ago | |

Was a bit to overzealous... Just read the readme. Looks pretty cool. Maybe I'll give it a try and see how it compares to the chess.com analysis (although I have to say that I never really use it).

pelican0 1 hour ago |

Very cool work!

Did you write the skills (text, and code) all by hand, or are those prompt outputs?

brumar 1 hour ago | |

Not by hand, no, the code was generated with claude code. The readme too, but with some extra efforts to avoid the awful ai generated readme.

It took multiple sessions to get to this result. At first I only generated annotated pgns and standalone html page inspired by lichess. The video generation was the cherry on top, it took few iterations too to fix issues and add markers and arrows. I only use consume the generated video these days, for the moment.

pelican0 35 minutes ago | | |

Makes sense, good use of the tools at hand. And the SKILL.md files, also generated similarly?

NietTim 56 minutes ago |

Neat! I've been slopping together various games to have AI play them, balatro, poker, blackjack, it's just so fun. Was just thinking about chess, wondering if, if I gave them an unrestricted sandbox, they'd start using existing solvers or not. They're surprisingly good at doing cardcounting, by the way.

yesitcan 21 minutes ago | |

I find it funny that a video game (Balatro) is lumped with poker and blackjack.

IMTDb 2 hours ago |

I am very interested in this, but it looks like the video link gives 404

brumar 2 hours ago | |

Weird, the video is supposed to be embedded. On my chrome desktop it displays properly. EDIT: fixed

TZubiri 38 minutes ago |

Writing skills files like this one don't seem to be the future of computing or AI, not by the quality, nor by the cost (15$ per usage?).

Also, you seem to have written the actual SKILL.md prompts themselves with AI? I don't know what to say that's insane, at least write the prompts? This idea of asking chatgpt to write the prompts for you is beyond lazy. Then presenting it as a project or tool of value to share to others is delusional.

Sorry for being harsh

Madmallard 1 hour ago |

"The result is not perfect" as LLMs are

"The fact that it reflects on my own thinking during the game makes it interesting from a teaching point of view, so I thought it was worth sharing." As AI the premium sycophantic scammer does

"but for me it is a much more pleasant and memorable experience than clicking around Stockfish branches"

And SO much less effective than doing the harder, more tedious feeling work

brumar 1 hour ago | |

The jury is out for the effectiveness, it's hard to debate this subject. From my cognitive background I know very well how important the generative effect is for learning. Maybe I'll add features that leverage generative/testing effect one day. Anyway, clicking on stockfish branches can be quite a passive activity too if done badly. I don't know how to do that well to be honest. My goal is often to just to understand what I missed, full stop.

For the sycophancy, I can say I did not feel that at all. When stockfish says your move suck, claude would have a hard time saying the opposite (no "you are absolutely right" when I am not).

Madmallard 1 hour ago | | |

Generative AI is really good at making you feel like you understand a lot without actually making you understand anything in-depth

Because lengthy difficult cognitively intensive labor is required for the brain to actually change its structure and connections

porridgeraisin 1 hour ago |

The elo of opus 5 models is 1300 or so. I wouldn't take chess lessons from a 1300.

brumar 1 hour ago | |

That was exactly my estimation when I played "raw" against Opus. But Opus with stockfish as a tool and much time available can, from what I experienced, generate good comments.

porridgeraisin 41 minutes ago | | |

Well yeah, of course. But also, analysing with stockfish is _also_ useless, unless you're a super GM.