u/tokentrillionaire

So I got bored and gave claude code a chessboard. I spend a lot of my day with claude in the terminal for work , I wanted a way to spin off and take a short break . I like chess and was curious if I could give claude a chessboard and play together, mini-game style and then come back to the work session.

https://i.redd.it/vqm3wpftvtjh1.gif

You say /chess in your session, a board opens in your browser, and the same claude is now your opponent.

You move on the board , the server uses chess.js to verify move legality , and then delivers the move to claude as an FEN notation in the chat via push in tmux or on a normal terminal as a long-poll pull., Claude then replies via the CLI and the board updates.

theres no engine behind it. no stockfish, nothing, its literally just claude reading the position and thinking. Which I found to be interesting as it would reflect about its moves.

Here are some quotes

"Nxe4 — that's a free pawn. e4 had nothing defending it. Castling was a reasonable-looking move that quietly left it hanging."

it almost blundered its queen and told on itself:

"I'll admit I first looked at the flashier Qd7 hitting both c6 and your loose g4 pawn — until I noticed your pawn would simply capture my queen. Crisis averted."

it plays little mind games:

"h3 — asking the bishop its intentions. Trade on f3 and I inherit the bishop pair for when the position opens; retreat and it's just lost time."

it got poetic about this bad position lol:

"your d6, f4 and h7 pawns are all long-term patients and my pieces have the better hospital beds."

it also has real clocks if you want them (rapid or classical, either side can lose on time), draw offers, resigns, takebacks. runs fully local, one npx command, MIT. the board doesnt actually care who the opponent is either, any terminal agent can sit in that seat.

repo: https://github.com/santiagoogaitnas/claude-chess

Let me know what you think!

So I got bored and gave claude code a chessboard. I spend a lot of my day with claude in the terminal for work , I wanted a way to spin off and take a short break . I like chess and was curious if I could give claude a chessboard and play together, mini-game style and then come back to the work session.

https://i.redd.it/ohve4pu9utjh1.gif

You say /chess in your session, a board opens in your browser, and the same claude is now your opponent.

You move on the board , the server uses chess.js to verify move legality , and then delivers the move to claude as an FEN notation in the chat via push in tmux or on a normal terminal as a long-poll pull., Claude then replies via the CLI and the board updates.

theres no engine behind it. no stockfish, nothing, its literally just claude reading the position and thinking. Which I found to be interesting as it would reflect about its moves.

Here are some quotes

"Nxe4 — that's a free pawn. e4 had nothing defending it. Castling was a reasonable-looking move that quietly left it hanging."

it almost blundered its queen and told on itself:

"I'll admit I first looked at the flashier Qd7 hitting both c6 and your loose g4 pawn — until I noticed your pawn would simply capture my queen. Crisis averted."

it plays little mind games:

"h3 — asking the bishop its intentions. Trade on f3 and I inherit the bishop pair for when the position opens; retreat and it's just lost time."

it got poetic about this bad position lol:

"your d6, f4 and h7 pawns are all long-term patients and my pieces have the better hospital beds."

it also has real clocks if you want them (rapid or classical, either side can lose on time), draw offers, resigns, takebacks. runs fully local, one npx command, MIT. the board doesnt actually care who the opponent is either, any terminal agent can sit in that seat.

repo: https://github.com/santiagoogaitnas/claude-chess

Let me know what you think!