MCP Time Server Node

Instructions

Implementation Reference

• src/tools/subtractTime.ts:10-38 (handler)

  The core handler function for the 'subtract_time' tool. It subtracts time by calling addTime with a negative amount, includes caching via withCache, timezone resolution, and debug logging.

  export function subtractTime(params: SubtractTimeParams): SubtractTimeResult {
    debug.timing('subtractTime called with params: %O', params);
  
    const { time, amount, unit, timezone } = params;
    const config = getConfig();
  
    // Determine the effective timezone for cache key
    const effectiveTimezone = resolveTimezone(timezone, config.defaultTimezone);
  
    // Use withCache wrapper instead of manual cache management
    return withCache(
      `subtract_${time}_${amount}_${unit}_${effectiveTimezone}`,
      CacheTTL.CALCULATIONS,
      () => {
        debug.timing('Delegating to addTime with negated amount: %d', -amount);
  
        // Subtraction is just addition with negative amount
        const result = addTime({
          time,
          amount: -amount, // Negate the amount
          unit,
          timezone,
        });
  
        debug.timing('subtractTime returning: %O', result);
        return result;
      }
    );
  }

• src/index.ts:97-113 (schema)

  Input schema for the 'subtract_time' tool, defining parameters, types, descriptions, and required fields.

  inputSchema: {
    type: 'object' as const,
    properties: {
      time: { type: 'string' as const, description: 'Base time' },
      amount: { type: 'number' as const, description: 'Amount to subtract' },
      unit: {
        type: 'string' as const,
        enum: ['years', 'months', 'days', 'hours', 'minutes', 'seconds'],
        description: 'Unit of time',
      },
      timezone: {
        type: 'string' as const,
        description: 'Timezone for calculation (default: system timezone)',
      },
    },
    required: ['time', 'amount', 'unit'],
  },

• src/index.ts:94-114 (registration)

  Registration of the 'subtract_time' tool in TOOL_DEFINITIONS array, including name, description, and schema.

  {
    name: 'subtract_time',
    description: 'Subtract duration from a date/time',
    inputSchema: {
      type: 'object' as const,
      properties: {
        time: { type: 'string' as const, description: 'Base time' },
        amount: { type: 'number' as const, description: 'Amount to subtract' },
        unit: {
          type: 'string' as const,
          enum: ['years', 'months', 'days', 'hours', 'minutes', 'seconds'],
          description: 'Unit of time',
        },
        timezone: {
          type: 'string' as const,
          description: 'Timezone for calculation (default: system timezone)',
        },
      },
      required: ['time', 'amount', 'unit'],
    },
  },

• src/index.ts:263-263 (registration)

  Mapping of 'subtract_time' to the subtractTime handler function in TOOL_FUNCTIONS object.

  subtract_time: (params: unknown) => subtractTime(params as Parameters<typeof subtractTime>[0]),

• src/types/index.ts:65-76 (schema)

  TypeScript type definitions for SubtractTimeParams (aliases AddTimeParams) and SubtractTimeResult (aliases TimeCalculationResult). Note: full AddTimeParams and TimeCalculationResult defined above in lines 58-72.

  export type SubtractTimeParams = AddTimeParams;
  
  export interface TimeCalculationResult {
    original: string;
    result: string;
    unix_original: number;
    unix_result: number;
  }
  
  // Type alias for consistency with test
  export type AddTimeResult = TimeCalculationResult;
  export type SubtractTimeResult = TimeCalculationResult;

• src/tools/index.ts:5-5 (registration)

  Export of subtractTime function from its module for use in src/index.ts.

  export { subtractTime } from './subtractTime';