MCP DateTime

Instructions

Implementation Reference

• src/server.ts:52-69 (handler)

  Handler function that validates the input timezone and returns the current time in that timezone using the helper function getCurrentTimeInTimezone, or an error if invalid.

  async (args) => {
    if (!isValidTimezone(args.timezone)) {
      return {
        content: [{ 
          type: "text", 
          text: `Error: Invalid timezone "${args.timezone}". Use the "list-timezones" tool to see available options.`
        }],
        isError: true
      };
    }
    
    return {
      content: [{ 
        type: "text", 
        text: `The current time in ${args.timezone} is ${getCurrentTimeInTimezone(args.timezone)}`
      }]
    };
  }

• src/server.ts:49-51 (schema)

  Input schema for the tool, defining a required 'timezone' string parameter.

  {
    timezone: z.string().describe("The timezone to get the current time for")
  },

• src/server.ts:46-70 (registration)

  Registration of the 'get-time-in-timezone' tool on the MCP server, including name, description, schema, and handler.

  server.tool(
    "get-time-in-timezone",
    "Get the current time in a specific timezone",
    {
      timezone: z.string().describe("The timezone to get the current time for")
    },
    async (args) => {
      if (!isValidTimezone(args.timezone)) {
        return {
          content: [{ 
            type: "text", 
            text: `Error: Invalid timezone "${args.timezone}". Use the "list-timezones" tool to see available options.`
          }],
          isError: true
        };
      }
      
      return {
        content: [{ 
          type: "text", 
          text: `The current time in ${args.timezone} is ${getCurrentTimeInTimezone(args.timezone)}`
        }]
      };
    }
  );

• src/timezone-utils.ts:52-60 (helper)

  Helper function to validate if a given timezone string is valid using Intl.DateTimeFormat.

  export function isValidTimezone(timezone: string): boolean {
    try {
      // Try to use the timezone with Intl.DateTimeFormat
      Intl.DateTimeFormat(undefined, { timeZone: timezone });
      return true;
    } catch (error) {
      return false;
    }
  }

• src/timezone-utils.ts:96-147 (helper)

  Core helper function that computes and formats the current date-time in the specified timezone using Intl APIs, returning an ISO8601-like string.

  export function getCurrentTimeInTimezone(timezone: string): string {
    try {
      const date = new Date();
      
      // Create a formatter that includes the timezone
      const options: Intl.DateTimeFormatOptions = {
        timeZone: timezone,
        timeZoneName: 'short'
      };
      
      // Get the timezone offset from the formatter
      const formatter = new Intl.DateTimeFormat('en-US', options);
      const formattedDate = formatter.format(date);
      const timezonePart = formattedDate.split(' ').pop() || '';
      
      // Format the date in ISO8601 format with the timezone
      // First get the date in the specified timezone
      const tzFormatter = new Intl.DateTimeFormat('en-US', {
        timeZone: timezone,
        year: 'numeric',
        month: '2-digit',
        day: '2-digit',
        hour: '2-digit',
        minute: '2-digit',
        second: '2-digit',
        hour12: false,
        fractionalSecondDigits: 3
      });
      
      const parts = tzFormatter.formatToParts(date);
      const dateParts: Record<string, string> = {};
      
      parts.forEach(part => {
        if (part.type !== 'literal') {
          dateParts[part.type] = part.value;
        }
      });
      
      // Format as YYYY-MM-DDTHH:MM:SS.sss±HH:MM (ISO8601)
      const isoDate = `${dateParts.year}-${dateParts.month}-${dateParts.day}T${dateParts.hour}:${dateParts.minute}:${dateParts.second}.${dateParts.fractionalSecond || '000'}`;
      
      // For proper ISO8601, we need to add the timezone offset
      // We can use the Intl.DateTimeFormat to get the timezone offset
      const tzOffset = new Date().toLocaleString('en-US', { timeZone: timezone, timeZoneName: 'longOffset' }).split(' ').pop() || '';
      
      // Format the final ISO8601 string
      return `${isoDate}${tzOffset.replace('GMT', '')}`;
    } catch (error) {
      console.error(`Error formatting time for timezone ${timezone}:`, error);
      return 'Invalid timezone';
    }
  }