ADB MCP Server

Implementation Reference

• src/index.ts:669-713 (handler)

  The handler function that executes the dump_image tool logic: runs 'adb shell screencap -p /sdcard/screenshot.png', pulls the PNG to a temp file, cleans up remote file, reads it, and returns base64 if requested or success message.

  async (args: z.infer<typeof AdbScreenshotSchema>, _extra: RequestHandlerExtra) => {
    log(LogLevel.INFO, "Taking device screenshot");
    
    const deviceArgs = buildDeviceArgs(args.device);
    const tempFilePath = createTempFilePath("adb-mcp", "screenshot.png");
    const remotePath = "/sdcard/screenshot.png";
    
    try {
      // Take screenshot on the device
      await runAdb([...deviceArgs, "shell", "screencap", "-p", remotePath]);
      
      // Pull the screenshot from the device
      await runAdb([...deviceArgs, "pull", remotePath, tempFilePath]);
      
      // Clean up the remote file
      await runAdb([...deviceArgs, "shell", "rm", remotePath]);
      
      // Read the screenshot file
      const imageData = await readFilePromise(tempFilePath);
      
      // Return as base64 or success message based on asBase64 parameter
      if (args.asBase64) {
        const base64Image = imageData.toString('base64');
        log(LogLevel.INFO, "Screenshot captured and converted to base64 successfully");
        return {
          content: [{ type: "text" as const, text: base64Image }]
        };
      } else {
        log(LogLevel.INFO, "Screenshot captured successfully");
        return {
          content: [{ type: "text" as const, text: "Screenshot captured successfully" }]
        };
      }
    } catch (error) {
      const errorMsg = error instanceof Error ? error.message : String(error);
      log(LogLevel.ERROR, `Error taking screenshot: ${errorMsg}`);
      return {
        content: [{ type: "text" as const, text: `Error taking screenshot: ${errorMsg}` }],
        isError: true
      };
    } finally {
      // Clean up the temporary file
      await cleanupTempFile(tempFilePath);
    }
  },

• src/types.ts:74-77 (schema)

  Base input schema object for dump_image tool parameters.

  export const dumpImageInputSchema = {
    device: z.string().optional().describe("Specific device ID (optional)"),
    asBase64: z.boolean().optional().default(false).describe("Return image as base64 (default: false)")
  };

• src/types.ts:108-108 (schema)

  Zod schema wrapper used for dump_image tool input validation in registration.

  export const AdbScreenshotSchema = z.object(dumpImageInputSchema);

• src/index.ts:666-715 (registration)

  MCP server.tool registration for the 'dump_image' tool, specifying name, input schema, handler function, and description.

  server.tool(
    "dump_image",
    AdbScreenshotSchema.shape,
    async (args: z.infer<typeof AdbScreenshotSchema>, _extra: RequestHandlerExtra) => {
      log(LogLevel.INFO, "Taking device screenshot");
      
      const deviceArgs = buildDeviceArgs(args.device);
      const tempFilePath = createTempFilePath("adb-mcp", "screenshot.png");
      const remotePath = "/sdcard/screenshot.png";
      
      try {
        // Take screenshot on the device
        await runAdb([...deviceArgs, "shell", "screencap", "-p", remotePath]);
        
        // Pull the screenshot from the device
        await runAdb([...deviceArgs, "pull", remotePath, tempFilePath]);
        
        // Clean up the remote file
        await runAdb([...deviceArgs, "shell", "rm", remotePath]);
        
        // Read the screenshot file
        const imageData = await readFilePromise(tempFilePath);
        
        // Return as base64 or success message based on asBase64 parameter
        if (args.asBase64) {
          const base64Image = imageData.toString('base64');
          log(LogLevel.INFO, "Screenshot captured and converted to base64 successfully");
          return {
            content: [{ type: "text" as const, text: base64Image }]
          };
        } else {
          log(LogLevel.INFO, "Screenshot captured successfully");
          return {
            content: [{ type: "text" as const, text: "Screenshot captured successfully" }]
          };
        }
      } catch (error) {
        const errorMsg = error instanceof Error ? error.message : String(error);
        log(LogLevel.ERROR, `Error taking screenshot: ${errorMsg}`);
        return {
          content: [{ type: "text" as const, text: `Error taking screenshot: ${errorMsg}` }],
          isError: true
        };
      } finally {
        // Clean up the temporary file
        await cleanupTempFile(tempFilePath);
      }
    },
    { description: ADB_DUMP_IMAGE_TOOL_DESCRIPTION }
  );