UniMCP4CC

#!/usr/bin/env node /** * Unity MCP Bridge Server * * This server bridges Claude Code and Unity Editor via MCP protocol. * No external dependencies required (uses Node.js built-in fetch API). * * Requirements: Node.js 18+ (for native fetch support) */ import { Server } from '@modelcontextprotocol/sdk/server/index.js'; import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js'; import { CallToolRequestSchema, ListToolsRequestSchema, } from '@modelcontextprotocol/sdk/types.js'; import fs from 'fs'; import path from 'path'; /** * Loads Unity HTTP port from .unity-mcp-runtime.json * Falls back to environment variable or default port */ function getUnityHttpUrl() { // First, try to read runtime config const runtimeConfigPath = path.join(process.cwd(), '.unity-mcp-runtime.json'); if (fs.existsSync(runtimeConfigPath)) { try { const config = JSON.parse(fs.readFileSync(runtimeConfigPath, 'utf8')); const url = `http://localhost:${config.httpPort}`; console.error(`[MCP Bridge] Using runtime config: ${url} (Project: ${config.projectName})`); return url; } catch (error) { console.error(`[MCP Bridge] Failed to read runtime config: ${error.message}`); } } // Fallback to environment variable or default const fallbackUrl = process.env.UNITY_HTTP_URL || 'http://localhost:5051'; console.error(`[MCP Bridge] Using fallback URL: ${fallbackUrl}`); return fallbackUrl; } const UNITY_HTTP_URL = getUnityHttpUrl(); // Verbose logging control (set via environment variable) const VERBOSE_LOGGING = process.env.MCP_VERBOSE === 'true'; function log(message) { console.error(message); } function verboseLog(message) { if (VERBOSE_LOGGING) { console.error(message); } } /** * HTTP request helper using native fetch (Node.js 18+) */ async function httpPost(url, data, timeout = 30000) { const controller = new AbortController(); const timeoutId = setTimeout(() => controller.abort(), timeout); try { const response = await fetch(url, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(data), signal: controller.signal, }); clearTimeout(timeoutId); if (!response.ok) { throw new Error(`HTTP ${response.status}: ${response.statusText}`); } return await response.json(); } catch (error) { clearTimeout(timeoutId); if (error.name === 'AbortError') { throw new Error(`Request timeout after ${timeout}ms`); } throw error; } } /** * HTTP GET request helper */ async function httpGet(url, timeout = 3000) { const controller = new AbortController(); const timeoutId = setTimeout(() => controller.abort(), timeout); try { const response = await fetch(url, { method: 'GET', signal: controller.signal, }); clearTimeout(timeoutId); if (!response.ok) { throw new Error(`HTTP ${response.status}: ${response.statusText}`); } return await response.json(); } catch (error) { clearTimeout(timeoutId); if (error.name === 'AbortError') { throw new Error(`Request timeout after ${timeout}ms`); } throw error; } } class UnityMCPServer { constructor() { this.server = new Server( { name: 'unity-mcp-server', version: '1.0.0', }, { capabilities: { tools: {}, }, } ); this.isUnityConnected = false; this.lastHealthCheck = null; this.healthCheckInterval = null; this.connectionWarningShown = false; this.setupHandlers(); this.setupErrorHandling(); } setupErrorHandling() { this.server.onerror = (error) => { console.error('[MCP Error]', error); }; process.on('SIGINT', async () => { this.stopHealthCheck(); await this.server.close(); process.exit(0); }); } /** * Checks if Unity Editor is running and responding */ async checkUnityHealth(silent = false) { try { const data = await httpGet(`${UNITY_HTTP_URL}/health`, 3000); if (data.status === 'ok') { const wasDisconnected = !this.isUnityConnected; this.isUnityConnected = true; this.lastHealthCheck = Date.now(); this.connectionWarningShown = false; // Always log on state change (initial connection or reconnection) if (wasDisconnected) { log(`[MCP Bridge] Connected to Unity Editor`); log(`[MCP Bridge] Project: ${data.projectName}`); log(`[MCP Bridge] Unity Version: ${data.unityVersion}`); } return true; } } catch (error) { const wasConnected = this.isUnityConnected; this.isUnityConnected = false; // Always show warning when connection is lost or not established if ((wasConnected || this.lastHealthCheck === null) && !this.connectionWarningShown) { if (wasConnected) { // Connection was lost - always show log(`\n[MCP Bridge] Lost connection to Unity Editor`); log(`[MCP Bridge] Error: ${error.message}`); log(`[MCP Bridge] Unity Editor may have been closed`); log(`[MCP Bridge] Waiting for reconnection...\n`); } else { // Initial connection failed - show once log(`[MCP Bridge] Unity Editor is not running`); log(`[MCP Bridge] Error: ${error.message}`); log(`[MCP Bridge] Please start Unity Editor`); } this.connectionWarningShown = true; } return false; } } /** * Starts periodic health check */ async startHealthCheck() { // Initial health check (verbose) await this.checkUnityHealth(false); // Check every 10 seconds (silent unless state changes) this.healthCheckInterval = setInterval(() => { this.checkUnityHealth(true); }, 10000); } /** * Stops periodic health check */ stopHealthCheck() { if (this.healthCheckInterval) { clearInterval(this.healthCheckInterval); this.healthCheckInterval = null; } } /** * Returns a user-friendly error message when Unity is not connected */ getDisconnectedErrorMessage() { return { content: [ { type: 'text', text: `Unity Editor is not running or not responding Please ensure: 1. Unity Editor is open 2. Unity MCP Server package is installed in your project 3. The Unity project is located at: ${process.cwd()} 4. HTTP server is running on port ${UNITY_HTTP_URL} Check Unity Console for error messages.`, }, ], isError: true, }; } setupHandlers() { this.server.setRequestHandler(ListToolsRequestSchema, async () => { try { // Check connection before making request if (!this.isUnityConnected) { verboseLog('[MCP Bridge] Unity not connected, attempting to connect...'); const isConnected = await this.checkUnityHealth(); if (!isConnected) { verboseLog('[MCP Bridge] Failed to connect to Unity Editor'); // Return empty tools list with warning return { tools: [], _meta: { warning: 'Unity Editor is not connected. Please start Unity Editor and ensure MCP Server is installed.' } }; } } const response = await httpPost(`${UNITY_HTTP_URL}/api/mcp`, { jsonrpc: '2.0', method: 'tools/list', params: {}, id: 1, }, 10000); const result = response.result || {}; return { tools: result.tools || [] }; } catch (error) { verboseLog('[MCP Bridge] Failed to list tools: ' + error.message); // Mark as disconnected this.isUnityConnected = false; return { tools: [], _meta: { error: `Failed to connect to Unity: ${error.message}` } }; } }); this.server.setRequestHandler(CallToolRequestSchema, async (request) => { try { // Check connection before making request if (!this.isUnityConnected) { verboseLog('[MCP Bridge] Unity not connected, attempting to connect...'); const isConnected = await this.checkUnityHealth(); if (!isConnected) { verboseLog('[MCP Bridge] Failed to connect to Unity Editor'); return this.getDisconnectedErrorMessage(); } } const { name, arguments: args } = request.params; const response = await httpPost(`${UNITY_HTTP_URL}/api/mcp`, { jsonrpc: '2.0', method: 'tools/call', params: { name, arguments: args || {}, }, id: 2, }, 30000); const result = response.result || {}; return { content: result.content || [ { type: 'text', text: JSON.stringify(result, null, 2), }, ], }; } catch (error) { // Mark as disconnected on error const wasConnected = this.isUnityConnected; this.isUnityConnected = false; const errorMessage = error.message; // If we just lost connection, provide detailed error if (wasConnected) { log('[MCP Bridge] Connection lost during API call: ' + errorMessage); return this.getDisconnectedErrorMessage(); } return { content: [ { type: 'text', text: `Error: ${errorMessage}`, }, ], isError: true, }; } }); } async run() { const transport = new StdioServerTransport(); await this.server.connect(transport); log('[MCP Bridge] Unity MCP Bridge server running on stdio'); if (VERBOSE_LOGGING) { log('[MCP Bridge] Verbose logging enabled (MCP_VERBOSE=true)'); } // Start health monitoring log('[MCP Bridge] Starting connection monitoring...'); await this.startHealthCheck(); } } const server = new UnityMCPServer(); server.run().catch(console.error);