Chessigma

Name: Chessigma
Author: chessigma

Chess opening guides and names, FEN and PGN checks, the daily chess puzzle and Elo estimates.

CommunityOnlineNo sign-inGlobalFreeRead-only

What it can do

What data it sees

Do you need an account

No: the server works without sign-in

Chess opening guides and names, FEN and PGN checks, the daily chess puzzle and Elo estimates.

How to connect

How to connect Chessigma to Claude

The server address to paste into Claude settings:

https://www.chessigma.com/api/mcp

Open Claude (claude.ai or the desktop app).
Go to Settings → Connectors.
Click Add custom connector.
Paste the server address copied below into Remote MCP server URL and click Add.
In a chat, click + → Connectors and switch the new connector on.

Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

Authorization

After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

How to connect Chessigma to ChatGPT

The server address to paste into ChatGPT settings:

https://www.chessigma.com/api/mcp

Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
Open Settings → Connectors and click Create.
Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
In a new chat open + → Apps/Connectors and enable the connector.

OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

Authorization

On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

How to connect Chessigma to Cursor

The server address to paste into Cursor settings:

https://www.chessigma.com/api/mcp

Fastest: click Open in Cursor below and confirm the prompt.

Manually:

In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
Save the file. The server appears in the MCP list; authorize it there if asked.

Authorization

If the service needs sign-in, an authorize button appears next to the server in the MCP list.

Server tool list (7)

Raw names from tools/list. Only developers need these.

get_opening_guide	Look up a chess opening by name or slug (for example "London System", "Caro-Kann" or "sicilian-defense") and return Chessigma's guide to it: the main line in SAN, a short summary, up to four key variations with the idea behind each, the strategy for each side, strengths and weaknesses. Full guides exist for 18 popular openings; any of about 3,700 catalogued opening names returns its name, ECO code and moves. When nothing matches, found is false and suggestions lists close names. Links open the opening's trainer and the analysis board on chessigma.com.
identify_opening	Identify the chess opening of a move sequence, given as SAN movetext ("1. e4 c5 2. Nf3 d6") or a full PGN. Returns the ECO code and name from a catalogue of about 3,700 named lines, how many half-moves (plies) followed known theory from move one, the first move that left it, a link to Chessigma's trainer when the opening has one, and a link that opens the moves on the chessigma.com analysis board.
analyze_position	Read a chess position from a FEN and return facts computed by the rules alone: side to move, status (normal, check, checkmate, stalemate or insufficient material), every legal move in SAN, the material count (pawn 1, knight 3, bishop 3, rook 5, queen 9) and the opening name when the position is a catalogued opening. This tool does not evaluate the position and does not choose a best move: the Stockfish engine runs in the user's browser at the returned analysisUrl (full analysis board) and bestMoveUrl (best move finder) on chessigma.com.
analyze_game	Summarize a chess game given as a PGN or as plain SAN movetext: players, result, number of plies, the opening and how long it followed theory, how the game ended (checkmate, stalemate, draw by rule, or unfinished or resigned) and the final position. Returns a link that opens the whole game on the chessigma.com analysis board, where the Stockfish engine runs in the user's browser, and, when the PGN's Link or Site tag is a Chess.com live game or a Lichess game, a link to that game's move-by-move review. It never evaluates moves itself and stores nothing.
review_online_game	Turn the link of a public Chess.com live game or a Lichess game into a chessigma.com link that imports the game and opens a move-by-move review, computed by Stockfish in the user's browser. Nothing is fetched when this tool runs: the game is read from Chess.com or Lichess only when the user opens the link. Chess.com daily (correspondence) games are not supported; ask for the PGN instead.
get_daily_puzzle	Get Chessigma's daily chess puzzle: today's by default, or a past day's via date (YYYY-MM-DD, from 2024-01-01 to today in UTC). The position (fen) is given with the solver to move, after the opponent's last move. The solution is in SAN, with the solver's moves at even indexes and the opponent's replies at odd ones. Do not reveal the solution unless the user asks for it. If today's puzzle is not out yet, the latest one is returned: check date. playUrl opens the puzzle on chessigma.com.
calculate_elo	Estimate a player's new Elo rating after a single game with the Elo formula. Pure arithmetic, no chess engine. The system field picks a K-factor default for FIDE, Chess.com or Lichess, but the result is an Elo estimate: Chess.com and Lichess use Glicko ratings, so their real rating changes differ.