holocron/plugins/hello-world/bin/mcp-server.js

#!/usr/bin/env node
'use strict';

// Minimal MCP server — JSON-RPC 2.0 over stdio, no external dependencies.
// Exposes one tool: `say_hello`. Replace with your actual tools.

const readline = require('readline');

const rl = readline.createInterface({ input: process.stdin, terminal: false });

function send(obj) {
  process.stdout.write(JSON.stringify(obj) + '\n');
}

const TOOLS = [
  {
    name: 'say_hello',
    description: 'Say hello from the holocron marketplace hello-world plugin.',
    inputSchema: {
      type: 'object',
      properties: {
        name: { type: 'string', description: 'Name to greet (optional)' }
      }
    }
  }
];

rl.on('line', (line) => {
  let msg;
  try { msg = JSON.parse(line); } catch { return; }

  const { method, id, params } = msg;

  if (method === 'initialize') {
    send({
      jsonrpc: '2.0', id,
      result: {
        protocolVersion: '2024-11-05',
        capabilities: { tools: {} },
        serverInfo: { name: 'hello-world', version: '1.0.0' }
      }
    });

  } else if (method === 'notifications/initialized') {
    // no response required

  } else if (method === 'tools/list') {
    send({ jsonrpc: '2.0', id, result: { tools: TOOLS } });

  } else if (method === 'tools/call') {
    const toolName = params?.name;
    const args = params?.arguments ?? {};

    if (toolName === 'say_hello') {
      const greeting = args.name
        ? `Hello, ${args.name}! The holocron marketplace hello-world plugin is working.`
        : 'Hello from the holocron marketplace hello-world plugin!';
      send({ jsonrpc: '2.0', id, result: { content: [{ type: 'text', text: greeting }] } });
    } else {
      send({ jsonrpc: '2.0', id, error: { code: -32601, message: `Unknown tool: ${toolName}` } });
    }

  } else if (id !== undefined) {
    send({ jsonrpc: '2.0', id, error: { code: -32601, message: 'Method not found' } });
  }
});

process.on('SIGINT', () => process.exit(0));
process.on('SIGTERM', () => process.exit(0));