mcp-helper-tools

Instructions

Implementation Reference

• src/tools/generator.ts:54-96 (handler)

  The handler function that executes the generateQRCode tool logic, supporting terminal, SVG, or base64 output formats using qrcode and qrcode-terminal libraries.

  handler: async ({
    data,
    type = 'terminal',
    errorCorrectionLevel = 'M'
  }: {
    data: string;
    type?: 'terminal' | 'svg' | 'base64';
    errorCorrectionLevel?: 'L' | 'M' | 'Q' | 'H'
  }) => {
    try {
      let result: string;
      const options = {
        errorCorrectionLevel,
        margin: 1,
        width: type === 'svg' ? 200 : undefined
      };
  
      switch (type) {
        case 'terminal':
          // Use qrcode-terminal for better terminal output
          result = await generateTerminalQR(data, { small: true });
          break;
        case 'svg':
          result = await QRCode.toString(data, { ...options, type: 'svg' });
          break;
        case 'base64':
          const buffer = await QRCode.toBuffer(data, { ...options, type: 'png' });
          result = `data:image/png;base64,${buffer.toString('base64')}`;
          break;
        default:
          throw new Error(`Unsupported output type: ${type}`);
      }
  
      return {
        content: [{
          type: 'text',
          text: result
        }]
      };
    } catch (error) {
      throw new Error(`QR code generation failed: ${error instanceof Error ? error.message : 'Unknown error'}`);
    }
  }

• src/tools/generator.ts:32-53 (schema)

  Input schema for the generateQRCode tool defining required 'data' and optional 'type' and 'errorCorrectionLevel' parameters.

  inputSchema: {
    type: 'object',
    properties: {
      data: {
        type: 'string',
        description: 'Data to encode in QR code'
      },
      type: {
        type: 'string',
        description: 'Output type (terminal, svg, or base64)',
        enum: ['terminal', 'svg', 'base64'],
        default: 'terminal'
      },
      errorCorrectionLevel: {
        type: 'string',
        description: 'Error correction level',
        enum: ['L', 'M', 'Q', 'H'],
        default: 'M'
      }
    },
    required: ['data']
  },

• src/index.ts:27-33 (registration)

  Registration of generatorTools (including generateQRCode) into the allTools object, which is used by the MCP server to list and call tools.

  const allTools: ToolKit = {
    ...encodingTools,
    ...geoTools,
    ...generatorTools,
    ...dateTimeTools,
    ...securityTools
  };

• src/index.ts:6-6 (registration)

  Import of generatorTools containing the generateQRCode tool definition.

  import { generatorTools } from './tools/generator.js';

• src/tools/generator.ts:7-9 (helper)

  Helper function to promisify qrcode-terminal.generate for use in the terminal QR code generation.

  const generateTerminalQR = promisify((text: string, opts: any, cb: (error: Error | null, result: string) => void) => {
    qrcodeTerminal.generate(text, opts, (result: string) => cb(null, result));
  });