pagecast

Instructions

Implementation Reference

• src/index.js:19-39 (handler)

  Registration of the 'record_page' tool in index.js, which calls startRecording.

  mcp.tool(
    'record_page',
    'Open a URL in a browser and start recording video. Returns a session ID. Call stop_recording when done. Common sizes: 1280x720 (16:9, README/YouTube), 1080x1920 (9:16, IG Reels/TikTok), 1080x1080 (1:1, Instagram/LinkedIn).',
    {
      url: z.string().describe('URL to open and record'),
      width: z.number().optional().default(1280).describe('Viewport width in pixels'),
      height: z.number().optional().default(720).describe('Viewport height in pixels')
    },
    async ({ url, width, height }) => {
      try {
        const result = await startRecording(url, { width, height });
        return {
          content: [{
            type: 'text',
            text: `Recording started!\n\nSession: ${result.sessionId}\nURL: ${result.url}\nStarted: ${result.startedAt}\n\nUse interact_page to scroll/click/hover during recording.\nCall stop_recording with sessionId "${result.sessionId}" when done.`
          }]
        };
      } catch (err) {
        return { content: [{ type: 'text', text: `Error: ${err.message}` }], isError: true };
      }
    }

• src/recorder.js:30-58 (handler)

  The startRecording function, which actually opens the Playwright page and initializes video recording.

  export async function startRecording(url, options = {}) {
    const b = await ensureBrowser();
  
    const width = options.width || 1280;
    const height = options.height || 720;
    const outputDir = options.outputDir || DEFAULT_OUTPUT_DIR;
    const sessionId = randomUUID().slice(0, 8);
  
    await mkdir(outputDir, { recursive: true });
  
    // Each context gets its own video recording
    const context = await b.newContext({
      recordVideo: {
        dir: outputDir,
        size: { width, height }
      },
      viewport: { width, height }
    });
  
    const page = await context.newPage();
  
    // Use 'load' instead of 'networkidle' — some pages never idle (WebSocket, polling)
    await page.goto(url, { waitUntil: 'load', timeout: 30_000 });
  
    const startedAt = new Date().toISOString();
    sessions.set(sessionId, { context, page, url, startedAt, outputDir });
  
    return { sessionId, url, startedAt };
  }