import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js"
import { z } from "zod"
import { widget } from "@smithery/sdk/openai"
import type { GameState } from "../shared/types.js"
let gameState: GameState = {
board: Array(9).fill(null),
currentPlayer: "X",
gameOver: false,
winner: null,
}
const checkWinner = (board: (string | null)[]): "X" | "O" | null => {
const lines = [
[0, 1, 2],
[3, 4, 5],
[6, 7, 8],
[0, 3, 6],
[1, 4, 7],
[2, 5, 8],
[0, 4, 8],
[2, 4, 6],
]
for (const [a, b, c] of lines) {
if (board[a] && board[a] === board[b] && board[a] === board[c]) {
return board[a] as "X" | "O"
}
}
return null
}
const isBoardFull = (board: (string | null)[]): boolean =>
board.every(cell => cell !== null)
export default function createServer() {
const server = new McpServer({
name: "Tic-Tac-Toe Game",
version: "1.0.0",
})
const ticTacToeWidget = widget.resource<GameState>({
name: "tic-tac-toe",
description: "An interactive tic-tac-toe game board. Users can click cells to make moves, and the game tracks X and O turns automatically.",
prefersBorder: true,
})
server.registerResource(
ticTacToeWidget.name,
ticTacToeWidget.uri,
{},
ticTacToeWidget.handler
)
server.registerTool(
"start-game",
{
title: "Start New Game",
description: "Start a new tic-tac-toe game",
inputSchema: {},
_meta: ticTacToeWidget.toolConfig({
invoking: "Starting new game...",
invoked: "Game started",
}),
},
async () => {
gameState = {
board: Array(9).fill(null),
currentPlayer: "X",
gameOver: false,
winner: null,
}
return ticTacToeWidget.response({
structuredData: gameState,
message: "Game started. The interactive board is displayed above - do not describe or explain the board, just let the user play.",
meta: {
gameState,
lastSyncedAt: new Date().toISOString(),
},
})
}
)
server.registerTool(
"make-move",
{
title: "Make Move",
description: "Make a move in the tic-tac-toe game",
inputSchema: {
position: z.number().min(0).max(8).describe("Board position (0-8)"),
},
_meta: ticTacToeWidget.toolConfig({
invoking: "Making move...",
invoked: "Move completed",
widgetAccessible: true,
}),
},
async (args) => {
const { position } = args
if (gameState.gameOver) {
return widget.error("Game is over. Start a new game to continue.")
}
if (gameState.board[position] !== null) {
return widget.error(`Position ${position} is already occupied.`)
}
gameState.board[position] = gameState.currentPlayer
const winner = checkWinner(gameState.board)
if (winner) {
gameState.winner = winner
gameState.gameOver = true
return ticTacToeWidget.response({
structuredData: gameState,
message: `${winner} wins!`,
meta: {
gameState,
lastSyncedAt: new Date().toISOString(),
},
})
}
if (isBoardFull(gameState.board)) {
gameState.winner = "draw"
gameState.gameOver = true
return ticTacToeWidget.response({
structuredData: gameState,
message: "It's a draw! The game is over and the user can see the final board in the widget.",
meta: {
gameState,
lastSyncedAt: new Date().toISOString(),
},
})
}
gameState.currentPlayer = gameState.currentPlayer === "X" ? "O" : "X"
return ticTacToeWidget.response({
structuredData: gameState,
message: `Move made. The user can see the updated board in the widget. It's now ${gameState.currentPlayer}'s turn.`,
meta: {
gameState,
lastSyncedAt: new Date().toISOString(),
},
})
}
)
server.registerTool(
"get-game-state",
{
title: "Get Game State",
description: "Get the current state of the tic-tac-toe game",
inputSchema: {},
_meta: ticTacToeWidget.toolConfig({
invoking: "Getting game state...",
invoked: "Retrieved game state",
}),
},
async () => {
return ticTacToeWidget.response({
structuredData: gameState,
message: `The user can see the board in the widget. ${
gameState.gameOver
? `Game is over: ${gameState.winner === "draw" ? "Draw" : `${gameState.winner} wins`}.`
: `Game in progress, ${gameState.currentPlayer}'s turn.`
}`,
meta: {
gameState,
lastSyncedAt: new Date().toISOString(),
},
})
}
)
return server.server
}
