Concurrent Browser MCP

Instructions

Implementation Reference

• src/tools.ts:890-933 (handler)

  Core handler implementation that captures screenshot of the entire page or a specific element using Playwright APIs, returns base64 encoded image.

  private async screenshot(instanceId: string, options: ScreenshotOptions, selector?: string): Promise<ToolResult> {
    const instance = this.browserManager.getInstance(instanceId);
    if (!instance) {
      return { success: false, error: `Instance ${instanceId} not found` };
    }
  
    try {
      let screenshotData: Buffer;
      
      if (selector) {
        const element = await instance.page.$(selector);
        if (!element) {
          return { success: false, error: `Element not found: ${selector}`, instanceId };
        }
        screenshotData = await element.screenshot({
          type: options.type,
          quality: options.type === 'jpeg' ? options.quality : undefined
        });
      } else {
        screenshotData = await instance.page.screenshot({
          fullPage: options.fullPage,
          type: options.type,
          quality: options.type === 'jpeg' ? options.quality : undefined,
          clip: options.clip
        });
      }
  
      return {
        success: true,
        data: { 
          screenshot: screenshotData.toString('base64'),
          type: options.type,
          selector
        },
        instanceId
      };
    } catch (error) {
      return {
        success: false,
        error: `Screenshot failed: ${error instanceof Error ? error.message : error}`,
        instanceId
      };
    }
  }

• src/tools.ts:359-394 (registration)

  Tool definition and registration in BrowserTools.getTools(), including name, description, and detailed input JSON schema.

  {
    name: 'browser_screenshot',
    description: 'Take a screenshot of the page or element',
    inputSchema: {
      type: 'object',
      properties: {
        instanceId: {
          type: 'string',
          description: 'Instance ID'
        },
        fullPage: {
          type: 'boolean',
          description: 'Whether to capture the full page',
          default: false
        },
        selector: {
          type: 'string',
          description: 'Element selector (capture specific element)'
        },
        type: {
          type: 'string',
          enum: ['png', 'jpeg'],
          description: 'Image format',
          default: 'png'
        },
        quality: {
          type: 'number',
          description: 'Image quality (1-100, JPEG only)',
          minimum: 1,
          maximum: 100,
          default: 80
        }
      },
      required: ['instanceId']
    }
  },

• src/tools.ts:562-568 (handler)

  Dispatcher in executeTools method that routes the tool call to the screenshot handler with parsed arguments.

  case 'browser_screenshot':
    return await this.screenshot(args.instanceId, {
      fullPage: args.fullPage || false,
      type: args.type || 'png',
      quality: args.quality || 80
    }, args.selector);