chromium-arm64

Instructions

Implementation Reference

• index.js:876-904 (handler)

  The main handler function for the 'run_performance_audit' tool. It ensures the Chromium instance is running, executes a JavaScript snippet via CDP to gather performance metrics (domContentLoaded, loadComplete, firstPaint, resourceCount, memoryUsage), parses the result, and returns formatted text output.

  async runPerformanceAudit() {
    await this.ensureChromium();
    
    const result = await this.sendCDPCommand('Runtime.evaluate', {
      expression: `
        const perfData = performance.getEntriesByType('navigation')[0];
        const timing = performance.timing;
        
        JSON.stringify({
          domContentLoaded: perfData ? Math.round(perfData.domContentLoadedEventEnd - perfData.domContentLoadedEventStart) : 0,
          loadComplete: perfData ? Math.round(perfData.loadEventEnd - perfData.loadEventStart) : 0,
          firstPaint: timing ? timing.loadEventEnd - timing.navigationStart : 0,
          resourceCount: performance.getEntriesByType('resource').length,
          memoryUsage: performance.memory ? {
            used: Math.round(performance.memory.usedJSHeapSize / 1024 / 1024),
            total: Math.round(performance.memory.totalJSHeapSize / 1024 / 1024),
            limit: Math.round(performance.memory.jsHeapSizeLimit / 1024 / 1024)
          } : 'Not available'
        });
      `,
      returnByValue: true
    });
    
    const performanceMetrics = JSON.parse(result.result?.value || '{}');
    
    return {
      content: [{ type: 'text', text: `Performance Audit Results:\\n${JSON.stringify(performanceMetrics, null, 2)}` }],
    };
  }

• index.js:287-294 (registration)

  Tool registration in the ListToolsRequestSchema handler. Defines the tool name, description, and input schema (empty object properties).

  {
    name: 'run_performance_audit',
    description: 'Run a performance audit on the current page',
    inputSchema: {
      type: 'object',
      properties: {},
    },
  },

• index.js:381-382 (registration)

  Dispatch case in the CallToolRequestSchema handler's switch statement that routes calls to the runPerformanceAudit method.

  case 'run_performance_audit':
    return await this.runPerformanceAudit();

• index.js:290-293 (schema)

  Input schema definition for the tool (accepts no parameters).

  inputSchema: {
    type: 'object',
    properties: {},
  },