MCP が欠けたまま始まったセッションを、どこで止めるか

// mcp-readiness.mjs — 設定のサーバーへ実際に接続し、見えているツール名を出します
// 使い方: node mcp-readiness.mjs <mcp_config.json> [必須ツール名 ...]
import { spawn } from 'node:child_process';
import { readFileSync } from 'node:fs';
 
const [configPath, ...required] = process.argv.slice(2);
const config = JSON.parse(readFileSync(configPath, 'utf8'));
const servers = config.mcpServers ?? config.servers ?? {};
 
const PROTOCOL_VERSION = '2025-06-18';
const TIMEOUT_MS = 8000;
 
function listTools(name, spec) {
  return new Promise((resolve) => {
    const child = spawn(spec.command, spec.args ?? [], {
      env: { ...process.env, ...(spec.env ?? {}) },
      stdio: ['pipe', 'pipe', 'pipe'],
    });
 
    let buffer = '';
    let settled = false;
    const done = (result) => {
      if (settled) return;
      settled = true;
      child.kill();
      resolve({ name, ...result });
    };
 
    const timer = setTimeout(
      () => done({ ok: false, reason: `${TIMEOUT_MS}ms 以内に応答がありません` }),
      TIMEOUT_MS,
    );
    child.on('error', (e) => { clearTimeout(timer); done({ ok: false, reason: e.message }); });
 
    const send = (msg) => child.stdin.write(JSON.stringify(msg) + '\n');
 
    child.stdout.on('data', (chunk) => {
      buffer += chunk;
      let index;
      while ((index = buffer.indexOf('\n')) >= 0) {
        const line = buffer.slice(0, index).trim();
        buffer = buffer.slice(index + 1);
        if (!line) continue;
        let msg;
        try { msg = JSON.parse(line); } catch { continue; } // ログ行が混ざることがあります
        if (msg.id === 1) {
          send({ jsonrpc: '2.0', method: 'notifications/initialized' });
          send({ jsonrpc: '2.0', id: 2, method: 'tools/list', params: {} });
        }
        if (msg.id === 2) {
          clearTimeout(timer);
          done({ ok: true, tools: (msg.result?.tools ?? []).map((t) => t.name) });
        }
      }
    });
 
    send({
      jsonrpc: '2.0',
      id: 1,
      method: 'initialize',
      params: {
        protocolVersion: PROTOCOL_VERSION,
        capabilities: {},
        clientInfo: { name: 'mcp-readiness', version: '1.0.0' },
      },
    });
  });
}
 
const results = await Promise.all(
  Object.entries(servers).map(([name, spec]) => listTools(name, spec)),
);
 
const seen = new Set();
for (const r of results) {
  if (r.ok) {
    r.tools.forEach((t) => seen.add(t));
    console.log(`OK   ${r.name}  ${r.tools.length} tools: ${r.tools.join(', ')}`);
  } else {
    console.log(`NG   ${r.name}  ${r.reason}`);
  }
}
 
const missing = required.filter((t) => !seen.has(t));
if (missing.length > 0) {
  console.log(`\n欠けている必須ツール: ${missing.join(', ')}`);
  process.exit(1);
}
console.log('\n必須ツールは揃っています');