Chess Coach

npx add-mcp 'https://chess-coach-246271308938.europe-west1.run.app/mcp'

Documentation

Chess Coach is a connector for Claude and ChatGPT that analyzes your Chess.com and Lichess games with the Stockfish engine and explains them in plain language, on an interactive board inside the chat. Every evaluation comes from the engine and every move description is computed from the rules of chess; Your assistant explains the engine results instead of guessing.

Setup

What you need

• A Claude or ChatGPT account. Chess Coach installs in one click from each assistant’s directory.
• A Chess.com or Lichess username. Chess Coach only reads your public, finished games: it never asks for your chess password.

Connect with Claude

1. Open Chess Coach in Claude’s directory.
2. Click Connect and sign in with your email (password or one-time code) or with Google. That creates your free Chess Coach account, with 14 days of full access.
3. Open a new chat, enable Chess Coach and tell Claude your username, for example: Analyze my last game. I'm magnus_fan on Chess.com. Chess Coach remembers your username for next time.

Connect once on the web or the desktop app, then use the same connection on mobile.

Claude Code and the Claude API

If you connected Chess Coach in claude.ai and log in to Claude Code with that account, it is already there: run /mcp to see it. Otherwise, add the server once and sign in:

claude mcp add --transport http chess-coach https://chess-coach-246271308938.europe-west1.run.app/mcp

Then run /mcp, select chess-coach and choose Authenticate to sign in with your Chess Coach account. The interactive board appears in the Claude apps; in Claude Code and through the API the tools return the same Stockfish analysis as text.

With the Claude API, use the MCP connector (beta mcp-client-2025-11-20): list the server URL in mcp_servers with your Chess Coach OAuth access token as authorization_token, and reference it from an mcp_toolset tool.

Connect with ChatGPT

1. Open Chess Coach in OpenAI’s plugin directory.
2. Click Install plugin, then Connect Chess Coach, and sign in with email or Google.
3. Open a Work chat, select @Chess Coach and send your chess username or a completed PGN.

Chess Coach was published on November 3, 2026. The same Chess Coach account works in Claude and ChatGPT. ChatGPT exposes the analysis and account tools; purchases and subscription management are not offered inside the plugin.

Example prompts

Show me my last 10 games on Chess.com (I'm magnus_fan) and let me pick one to analyze. Analyze my last game in depth. Find my game against aleks_92 from March 2024 and review it. Why was my bishop move on move 15 a mistake? What should I have played? Show me in a board the three moments where I could have played better. Which openings cost me the most points with black? I play kate_plays on Lichess tomorrow. How should I prepare? Explain it more technically, with notation and numbers.

The interactive board

When Chess Coach reviews a game, your assistant shows the real game on an interactive board in the chat:

• Key moments ①②③: the two or three moments that teach you the most, numbered like your assistant's explanation below the board. Tap a number, or use the ‹ › arrows, to jump there.
• Arrows: the green arrow is the better move. Step through every move with the buttons or your keyboard.
• Try your own ideas: drag a piece to explore a line and ask Stockfish to evaluate it.
• Why?: the question buttons send your question about the position on screen straight to your assistant.
• Practice mistakes: replay the positions where you went wrong and find the better move.

For follow-up questions your assistant can also show smaller boards, several of them as a carousel. The board is in English; your assistant answers in your language.

Tools

The analysis and account tools work in both assistants. The subscription tools below are available in Claude; in ChatGPT, manage your plan on this website.

Tool	What it does	Access
list_games	Lists your finished games and searches your whole history by month, opponent, result, color, time control or opening.	Read-only
review_game	In-depth Stockfish review of the game you choose, with the interactive board, key moments and mistake practice.	Read-only · 1 review
show_board	Shows one or more positions on a mini board with arrows for the move played and the better move.	Read-only
analyze_position	Best moves and lines for a position or a line you want to explore; explains illegal moves.	Read-only
opening_report	Your opening repertoire (or an opponent's) with scores and the weakest lines.	Read-only
player_report	Scores five areas of your play from up to 30 games, the most recent ones or those of a period (for example September to October, rapid games only): blunders, tactics, clock, converting won positions and openings.	Read-only · Trial, Plus/Pro
training_drills	Turns your own mistakes from up to 30 games, recent or from a period, into puzzles to practice.	Read-only · Trial, Plus/Pro
set_chess_username	Saves your Chess.com or Lichess username.	Writes your settings
set_explanation_level	Saves how you want explanations: beginner (default), intermediate or advanced.	Writes your settings
my_account	Shows your plan, the days left in your trial and what you've used today.	Read-only
upgrade_plan	Returns a secure Stripe checkout link when you ask to upgrade.	Account
manage_subscription	Returns your Stripe customer portal link to see invoices, change your card or cancel.	Account
board_event	Board diagnostics. Only the interactive board calls it, never your assistant: it records the board action (tab, lesson, question, practice answer or a failure), the app's name and version and short error texts. No moves, positions or conversation text. See the privacy policy.	Writes diagnostics

Plans and limits

• Free trial (first 14 days of every account, no card needed): everything in Pro, that is up to 20 in-depth reviews per day, the five-area report and drills from your own mistakes, for up to 30 games at once or a whole period. When it ends you move to Free unless you choose a plan.
• Free: 1 in-depth game review per day, the interactive board and practice, opening reports and 30 position checks per day.
• Plus ($3.99/month): 10 reviews per day, the five-area report and drills from your own mistakes.
• Pro ($7.99/month): unlimited reviews with fair use (up to 20 per day).

Reports and drills count one review per 8 games they analyze. Ask Claude “How many trial days do I have left?” or open My account to see when your trial ends. To upgrade, ask Claude (“I want Plus”) or open My account; payment happens on Stripe's secure page. To cancel, change plan or update your card, use My account or ask Claude to manage your subscription. Limits reset every day at midnight UTC.

Troubleshooting

My assistant asks me to sign in again

Your session expired or the connector was updated. In Claude, open Customize → Connectors; in ChatGPT, open Plugins. Select Chess Coach and reconnect.

It can't find my username or game

Check the spelling and the platform (Chess.com or Lichess). Only finished, public games can be analyzed. For an old game, give the month or paste the game link; you can also paste its PGN.

The interactive board doesn't appear

Start a new chat after connecting, and make sure your Claude app is up to date. If the board still doesn't show, Claude explains the review in text and you can follow it on Chess.com or Lichess.

“You've already used today's free review”

After the 14-day trial, the free plan includes one in-depth review per day. It resets the next day, or you can upgrade.

“The platform is rate-limiting our requests”

Chess.com or Lichess is temporarily limiting requests. Wait a minute and try again.

A move is “not legal”

When you explore a line, Chess Coach checks every move against the rules and explains why a move isn't possible, for example because a piece is pinned to its king.

Data and privacy

Chess Coach only receives the parameters of each request (a username, a game link, a position), never your conversation with Claude. It reads public game data from Chess.com and Lichess and never asks for your chess password. It doesn't sell data, show ads or train AI models with your games. Details in the privacy policy and the terms.