MCP Time Server Node

import { Server } from '@modelcontextprotocol/sdk/server/index.js'; import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js'; import { CallToolRequestSchema, ListToolsRequestSchema } from '@modelcontextprotocol/sdk/types.js'; // Research how MCP server setup works async function researchMCPServer() { console.log('=== MCP Server Research ===\n'); // 1. Basic server creation console.log('1. Server Creation:'); try { // Look at the constructor signature from the types const serverInfo = { name: 'test-server', version: '1.0.0', }; const options = { capabilities: { tools: {}, }, }; new Server(serverInfo, options); console.log('✓ Server created successfully'); console.log(` - Implementation info provided to constructor`); console.log(` - Options include capabilities`); } catch (error) { console.log('✗ Server creation failed:', error); } // 2. Tool registration pattern console.log('\n2. Tool Registration:'); const testServer = new Server( { name: 'test-server', version: '1.0.0', }, { capabilities: { tools: {}, }, }, ); // Research tool list handler testServer.setRequestHandler(ListToolsRequestSchema, async () => { console.log(' - tools/list handler called'); return { tools: [ { name: 'test_tool', description: 'A test tool', inputSchema: { type: 'object', properties: { message: { type: 'string' }, }, required: ['message'], }, }, ], }; }); // Research tool call handler testServer.setRequestHandler(CallToolRequestSchema, async (request) => { console.log(' - tools/call handler called'); console.log(` - Tool name: ${request.params.name}`); console.log(` - Tool arguments:`, request.params.arguments); if (request.params.name === 'test_tool') { return { content: [ { type: 'text', text: `Received: ${JSON.stringify(request.params.arguments)}`, }, ], }; } throw new Error(`Unknown tool: ${request.params.name}`); }); console.log('✓ Request handlers set'); // 3. Transport setup console.log('\n3. Transport Setup:'); try { new StdioServerTransport(); console.log('✓ StdioServerTransport created'); console.log(' - Uses process.stdin and process.stdout for communication'); // Note: Don't actually run the transport in research // await testServer.connect(transport); console.log(' - Server would connect to transport with server.connect(transport)'); console.log(' - This starts the JSON-RPC message loop'); } catch (error) { console.log('✗ Transport setup failed:', error); } // 4. Error handling patterns console.log('\n4. Error Handling:'); console.log(' - MCP errors should use McpError class'); console.log(' - Tool errors should return error in response'); console.log(' - Example error response:'); console.log(' { error: { code: "INVALID_PARAMS", message: "...", details: {...} } }'); // 5. Schema validation console.log('\n5. Schema Validation:'); console.log(' - SDK uses request schemas for validation'); console.log(' - ListToolsRequestSchema validates tools/list requests'); console.log(' - CallToolRequestSchema validates tools/call requests'); console.log(' - Input validation happens automatically'); // 6. Tool response format console.log('\n6. Tool Response Format:'); console.log(' - Tools must return { content: [...] }'); console.log(' - Content items have type: "text" or "image"'); console.log(' - Text content: { type: "text", text: "..." }'); console.log(' - Errors: throw or return error object'); // 7. Multiple tools pattern console.log('\n7. Multiple Tools Pattern:'); console.log(' - All tools handled in single CallToolRequestSchema handler'); console.log(' - Switch on request.params.name'); console.log(' - Import tool functions and call based on name'); console.log(' - Map tool names to functions for cleaner code'); // 8. Environment and configuration console.log('\n8. Environment Configuration:'); console.log(' - Can read from process.env for configuration'); console.log(' - Common env vars: NODE_ENV, CACHE_SIZE, RATE_LIMIT'); console.log(' - Server info (name, version) typically from package.json'); // 9. Async patterns console.log('\n9. Async Patterns:'); console.log(' - All handlers are async'); console.log(' - Tool functions can be async'); console.log(' - Errors in async functions are caught by SDK'); // 10. Testing considerations console.log('\n10. Testing Considerations:'); console.log(' - Can test handlers directly without transport'); console.log(' - Mock request objects for handler testing'); console.log(' - Test tool registration separately from execution'); console.log(' - Verify error handling for unknown tools'); // 11. Tool input schemas console.log('\n11. Tool Input Schemas:'); console.log(' - Input schemas use JSON Schema format'); console.log(' - Common properties: type, properties, required'); console.log(' - Support for various types: string, number, boolean, object, array'); console.log(' - Can include descriptions for each property'); // 12. Method names from schemas console.log('\n12. Request Methods:'); console.log(` - ListToolsRequestSchema method: ${ListToolsRequestSchema.shape.method.value}`); console.log(` - CallToolRequestSchema method: ${CallToolRequestSchema.shape.method.value}`); } // Run research researchMCPServer().catch(console.error);