Date MCP Server

Instructions

Implementation Reference

• src/index.ts:57-84 (handler)

  The handler function implementing the 'get-day-of-week' tool. It parses an optional date (YYYY-MM-DD) or uses today, validates it, determines the day of the week using toLocaleDateString and getDay(), handles errors for invalid date or locale, and returns structured JSON content.

  async ({ date, locale = 'en-US' }) => {
    const targetDate = date ? new Date(date + 'T00:00:00') : new Date();
  
    if (isNaN(targetDate.getTime())) {
      return {
        content: [{ type: 'text', text: 'Error: Invalid date format. Use YYYY-MM-DD.' }],
        isError: true
      };
    }
  
    try {
      return {
        content: [{
          type: 'text',
          text: JSON.stringify({
            dayName: targetDate.toLocaleDateString(locale, { weekday: 'long' }),
            dayNumber: targetDate.getDay(),
            date: targetDate.toISOString().split('T')[0]
          }, null, 2)
        }]
      };
    } catch {
      return {
        content: [{ type: 'text', text: `Error: Invalid locale "${locale}".` }],
        isError: true
      };
    }
  }

• src/index.ts:49-56 (schema)

  Input schema for the 'get-day-of-week' tool using Zod, defining optional 'date' (YYYY-MM-DD) and 'locale' parameters with descriptions.

  {
    title: 'Get Day of Week',
    description: 'Returns the day of the week for a given date or today.',
    inputSchema: {
      date: z.string().optional().describe('Date in YYYY-MM-DD format (defaults to today)'),
      locale: z.string().optional().describe('Locale for day name (e.g., "en-US", "de-DE")')
    }
  },

• src/index.ts:47-85 (registration)

  The server.registerTool call registering the 'get-day-of-week' tool with its name, schema, and handler function.

  server.registerTool(
    'get-day-of-week',
    {
      title: 'Get Day of Week',
      description: 'Returns the day of the week for a given date or today.',
      inputSchema: {
        date: z.string().optional().describe('Date in YYYY-MM-DD format (defaults to today)'),
        locale: z.string().optional().describe('Locale for day name (e.g., "en-US", "de-DE")')
      }
    },
    async ({ date, locale = 'en-US' }) => {
      const targetDate = date ? new Date(date + 'T00:00:00') : new Date();
  
      if (isNaN(targetDate.getTime())) {
        return {
          content: [{ type: 'text', text: 'Error: Invalid date format. Use YYYY-MM-DD.' }],
          isError: true
        };
      }
  
      try {
        return {
          content: [{
            type: 'text',
            text: JSON.stringify({
              dayName: targetDate.toLocaleDateString(locale, { weekday: 'long' }),
              dayNumber: targetDate.getDay(),
              date: targetDate.toISOString().split('T')[0]
            }, null, 2)
          }]
        };
      } catch {
        return {
          content: [{ type: 'text', text: `Error: Invalid locale "${locale}".` }],
          isError: true
        };
      }
    }
  );