Memory MCP Server

Instructions

Implementation Reference

• src/index.js:191-193 (handler)

  Handler function for the 'get_metrics' MCP tool. It executes the tool logic by calling globalMetrics.getMetrics() to retrieve comprehensive server performance metrics.

  async handler() {
    return globalMetrics.getMetrics();
  }

• src/index.js:186-194 (registration)

  Registration of the 'get_metrics' tool in the tool registry. Includes name, description, empty input schema (no parameters), system scope, and inline handler.

  registerTool({
    name: 'get_metrics',
    description: '獲取服務器性能指標',
    inputSchema: z.object({}),
    scope: 'system',
    async handler() {
      return globalMetrics.getMetrics();
    }
  }, 'system');

• src/index.js:189-189 (schema)

  Zod input schema for the 'get_metrics' tool: empty object schema indicating no input parameters are required.

  inputSchema: z.object({}),

• src/monitoring/metrics.js:130-194 (helper)

  Core implementation of getMetrics() method in MetricsCollector class. Computes and returns detailed performance metrics: uptime, request counts/error rates, latency percentiles (p50/p95/p99), cache statistics, memory usage, and tool-specific stats.

  getMetrics() {
    const now = Date.now();
    const uptime = now - this.startTime;
    const uptimeSeconds = Math.floor(uptime / 1000);
  
    // 計算請求率
    const requestsPerSecond = this.requestCount / (uptimeSeconds || 1);
  
    // 計算錯誤率
    const errorRate = this.requestCount > 0
      ? (this.errorCount / this.requestCount * 100).toFixed(2)
      : 0;
  
    // 計算持續時間統計
    const avgDuration = this.durations.length > 0
      ? this.durations.reduce((sum, d) => sum + d, 0) / this.durations.length
      : 0;
  
    // 計算緩存命中率
    const totalCacheAccess = this.cacheHits + this.cacheMisses;
    const cacheHitRate = totalCacheAccess > 0
      ? (this.cacheHits / totalCacheAccess * 100).toFixed(2)
      : 0;
  
    // 獲取最新內存使用
    const latestMemory = this.memorySnapshots.length > 0
      ? this.memorySnapshots[this.memorySnapshots.length - 1]
      : process.memoryUsage();
  
    return {
      uptime: {
        ms: uptime,
        seconds: uptimeSeconds,
        human: this.formatUptime(uptimeSeconds)
      },
      requests: {
        total: this.requestCount,
        success: this.successCount,
        error: this.errorCount,
        errorRate: `${errorRate}%`,
        requestsPerSecond: requestsPerSecond.toFixed(2)
      },
      latency: {
        avg: avgDuration.toFixed(2),
        p50: percentile(this.durations, 0.50).toFixed(2),
        p95: percentile(this.durations, 0.95).toFixed(2),
        p99: percentile(this.durations, 0.99).toFixed(2),
        max: this.durations.length > 0 ? Math.max(...this.durations).toFixed(2) : 0,
        unit: 'ms'
      },
      cache: {
        hits: this.cacheHits,
        misses: this.cacheMisses,
        total: totalCacheAccess,
        hitRate: `${cacheHitRate}%`
      },
      memory: {
        rss: `${(latestMemory.rss / 1024 / 1024).toFixed(2)} MB`,
        heapTotal: `${(latestMemory.heapTotal / 1024 / 1024).toFixed(2)} MB`,
        heapUsed: `${(latestMemory.heapUsed / 1024 / 1024).toFixed(2)} MB`,
        external: `${(latestMemory.external / 1024 / 1024).toFixed(2)} MB`
      },
      toolStats: this.getToolStats()
    };
  }