docs: add example for connecting via --browserUrl (9222)

Author: root

examples/remote-debugging-9222.mjs

@@ -0,0 +1,67 @@
+// Example: connect to a Chrome instance that was started with a remote debugging port.
+//
+// 1) Start Chrome manually with remote debugging enabled, e.g.:
+//    macOS:
+//      /Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --remote-debugging-port=9222
+//    Linux:
+//      google-chrome --remote-debugging-port=9222
+//
+// 2) Run this script:
+//      node examples/remote-debugging-9222.mjs
+//
+// This spawns the MCP server and connects it to http://127.0.0.1:9222 via --browserUrl.
+//
+// Note: This is intentionally a small template you can adapt for your own MCP client.
+
+import { spawn } from 'node:child_process';
+
+const DEBUG_URL = process.env.CHROME_DEBUG_URL ?? 'http://127.0.0.1:9222';
+
+const child = spawn(
+  'npx',
+  ['--yes', 'chrome-devtools-mcp@latest', '--browserUrl', DEBUG_URL],
+  {
+    stdio: ['pipe', 'pipe', 'pipe'],
+    env: {
+      ...process.env,
+      CHROME_DEVTOOLS_MCP_NO_USAGE_STATISTICS: 'true',
+    },
+  },
+);
+
+child.stderr.on('data', (d) => process.stderr.write(d));
+
+let buf = '';
+child.stdout.on('data', (d) => {
+  buf += d.toString('utf8');
+  let idx;
+  while ((idx = buf.indexOf('\n')) !== -1) {
+    const line = buf.slice(0, idx).trim();
+    buf = buf.slice(idx + 1);
+    if (!line) continue;
+    try {
+      const msg = JSON.parse(line);
+      console.log('←', msg);
+      // Exit after initialize.
+      if (msg.id === 1) {
+        child.kill();
+        process.exit(0);
+      }
+    } catch {
+      // ignore non-JSON lines
+    }
+  }
+});
+
+const init = {
+  jsonrpc: '2.0',
+  id: 1,
+  method: 'initialize',
+  params: {
+    protocolVersion: '2024-11-05',
+    capabilities: {},
+    clientInfo: { name: 'remote-debugging-9222', version: '0.0.0' },
+  },
+};
+
+child.stdin.write(JSON.stringify(init) + '\n');