MCP Tauri Automation

Instructions

Implementation Reference

• src/tools/screenshot.ts:11-42 (handler)

  Primary handler function for the 'capture_screenshot' tool. Processes input parameters, invokes the TauriDriver's screenshot method, and returns a standardized ToolResponse with base64 data or file path.

  export async function captureScreenshot(
    driver: TauriDriver,
    params: ScreenshotParams = {}
  ): Promise<ToolResponse<{ path?: string; base64?: string; message: string }>> {
    try {
      const returnBase64 = params.returnBase64 ?? true; // Default to base64 for MCP
      const result = await driver.captureScreenshot(params.filename, returnBase64);
  
      if (returnBase64) {
        return {
          success: true,
          data: {
            base64: result,
            message: 'Screenshot captured successfully',
          },
        };
      } else {
        return {
          success: true,
          data: {
            path: result,
            message: `Screenshot saved to: ${result}`,
          },
        };
      }
    } catch (error) {
      return {
        success: false,
        error: error instanceof Error ? error.message : String(error),
      };
    }
  }

• src/index.ts:232-260 (handler)

  MCP server CallToolRequest handler case for 'capture_screenshot'. Calls the tool function and formats the response, including special handling for image content in MCP format.

  case 'capture_screenshot': {
    const result = await captureScreenshot(driver, args as any);
  
    if (result.success && result.data?.base64) {
      // Return both text description and image
      return {
        content: [
          {
            type: 'text',
            text: result.data.message,
          },
          {
            type: 'image',
            data: result.data.base64,
            mimeType: 'image/png',
          },
        ],
      };
    }
  
    return {
      content: [
        {
          type: 'text',
          text: JSON.stringify(result, null, 2),
        },
      ],
    };
  }

• src/index.ts:84-101 (registration)

  Registration of the 'capture_screenshot' tool in the MCP server's ListToolsRequest handler, including name, description, and input schema.

  {
    name: 'capture_screenshot',
    description: 'Capture a screenshot of the application window. Returns base64-encoded PNG image data by default.',
    inputSchema: {
      type: 'object',
      properties: {
        filename: {
          type: 'string',
          description: 'Optional filename (without extension) to save the screenshot. If not provided, a timestamp will be used.',
        },
        returnBase64: {
          type: 'boolean',
          description: 'Whether to return base64 image data (true) or save to file and return path (false). Default: true',
          default: true,
        },
      },
    },
  },

• src/tauri-driver.ts:99-115 (helper)

  Low-level implementation in TauriDriver class that captures the screenshot using WebDriverIO's takeScreenshot(), returns base64 or saves to file.

  async captureScreenshot(filename?: string, returnBase64: boolean = false): Promise<string> {
    this.ensureAppRunning();
  
    const screenshot = await this.appState.browser!.takeScreenshot();
  
    if (returnBase64) {
      return screenshot;
    }
  
    // Save to file
    const timestamp = new Date().toISOString().replace(/[:.]/g, '-');
    const fileName = filename ? `${filename}.png` : `screenshot-${timestamp}.png`;
    const filePath = path.join(this.config.screenshotDir, fileName);
  
    await fs.writeFile(filePath, screenshot, 'base64');
    return filePath;
  }