DateTime MCP Server

#!/usr/bin/env node /** * This MCP server provides the current date and time with timezone support. */ import { Server } from "@modelcontextprotocol/sdk/server/index.js"; import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js"; import { CallToolRequestSchema, ListToolsRequestSchema, McpError, ErrorCode, } from "@modelcontextprotocol/sdk/types.js"; import { formatInTimeZone } from "date-fns-tz"; /** * Configuration interface for server timezone settings */ interface ServerConfig { defaultTimezone?: string; } /** * Tool arguments interface for timezone parameter */ interface DateTimeToolArgs { timezone?: string; } /** * Validates if a timezone identifier is supported * @param timezone - The timezone identifier to validate * @returns true if valid, false otherwise */ function isValidTimezone(timezone: string): boolean { try { // Use Intl.supportedValuesOf to get all supported timezones // This is more robust than try/catch with toLocaleString if (typeof Intl !== 'undefined' && 'supportedValuesOf' in Intl) { const supportedTimezones = Intl.supportedValuesOf('timeZone'); return supportedTimezones.includes(timezone); } // Fallback: Try to create a date and format it in the timezone // If it throws, the timezone is invalid new Intl.DateTimeFormat('en', { timeZone: timezone }).format(new Date()); return true; } catch { return false; } } /** * Gets the default timezone from environment or configuration * @param config - Server configuration object * @returns The default timezone to use */ function getDefaultTimezone(config?: ServerConfig): string { // Priority: config.defaultTimezone > process.env.TZ > 'UTC' if (config?.defaultTimezone && isValidTimezone(config.defaultTimezone)) { return config.defaultTimezone; } if (process.env.TZ && isValidTimezone(process.env.TZ)) { return process.env.TZ; } return 'UTC'; } /** * Server configuration - can be extended to read from config file or environment */ const serverConfig: ServerConfig = { // You can set a default timezone here, or it will use process.env.TZ or fallback to UTC // defaultTimezone: 'America/New_York', // Example: set default timezone }; /** * Create an MCP server with capabilities for tools. */ const server = new Server( { name: "datetime-mcp", version: "0.2.0", description: "An MCP server that provides LLMs with current date and time context with timezone support.", }, { capabilities: { tools: {}, }, } ); /** * Handler that lists available tools. * Exposes a single "get_current_datetime" tool with timezone support. */ server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools: [ { name: "get_current_datetime", description: "Get the current server date and time. Optionally specify a timezone (e.g., 'America/New_York', 'Europe/London', 'Asia/Tokyo'). Defaults to server's configured timezone or UTC.", inputSchema: { type: "object", properties: { timezone: { type: "string", description: "Optional timezone identifier (e.g., 'America/New_York', 'Europe/London', 'Asia/Tokyo'). If not provided, uses the server's default timezone or UTC." } }, } } ] }; }); /** * Handler for the get_current_datetime tool. * Returns the current date and time with timezone support. */ server.setRequestHandler(CallToolRequestSchema, async (request) => { switch (request.params.name) { case "get_current_datetime": { try { const args = request.params.arguments as DateTimeToolArgs | undefined; const requestedTimezone = args?.timezone; // Determine which timezone to use let timezone: string; if (requestedTimezone) { // User provided a timezone parameter - validate it if (!isValidTimezone(requestedTimezone)) { throw new McpError( ErrorCode.InvalidParams, `Invalid timezone: ${requestedTimezone}. Please use a valid IANA timezone identifier (e.g., 'America/New_York', 'Europe/London', 'Asia/Tokyo').` ); } timezone = requestedTimezone; } else { // Use default timezone from server config or fallback timezone = getDefaultTimezone(serverConfig); } const now = new Date(); // Format the datetime in the specified timezone let dateTimeString: string; let timezoneInfo: string; if (timezone === 'UTC') { // For UTC, use the standard ISO format dateTimeString = now.toISOString(); timezoneInfo = 'UTC'; } else { // For other timezones, use date-fns-tz to format in the timezone // Format as ISO-like string but with timezone offset const formatPattern = "yyyy-MM-dd'T'HH:mm:ss.SSSxxx"; dateTimeString = formatInTimeZone(now, timezone, formatPattern); timezoneInfo = timezone; } // Create a user-friendly response const responseText = requestedTimezone ? `The current date and time in ${timezoneInfo} is: ${dateTimeString}` : `The current date and time is: ${dateTimeString} (${timezoneInfo})`; return { content: [{ type: "text", text: responseText }] }; } catch (error) { // Re-throw McpErrors as-is if (error instanceof McpError) { throw error; } // Wrap other errors in an McpError throw new McpError( ErrorCode.InternalError, `Failed to get current datetime: ${error instanceof Error ? error.message : 'Unknown error'}` ); } } default: // Use McpError for standard MCP errors throw new McpError(ErrorCode.MethodNotFound, `Unknown tool: ${request.params.name}`); } }); /** * Start the server using stdio transport. * This allows the server to communicate via standard input/output streams. */ async function main() { const transport = new StdioServerTransport(); // Add error handler server.onerror = (error) => console.error('[MCP Error]', error); await server.connect(transport); // Log that the server is running to stderr so it doesn't interfere with stdout JSON communication console.error('DateTime MCP server running on stdio'); } main().catch((error) => { console.error("Server failed to start:", error); process.exit(1); });