diff --git a/.tangled/workflows/ci.yaml b/.tangled/workflows/ci.yaml
index cacd2da..2ac8c6d 100644
--- a/.tangled/workflows/ci.yaml
+++ b/.tangled/workflows/ci.yaml
@@ -1,6 +1,6 @@
 when:
   - event: ['push', 'pull_request']
-    branch: ['*']
+    branch: ['**']
 
 engine: nixery
 
diff --git a/test/serve/fd-dup-diag.test.ts b/test/serve/fd-dup-diag.test.ts
index f68e447..c402c85 100644
--- a/test/serve/fd-dup-diag.test.ts
+++ b/test/serve/fd-dup-diag.test.ts
@@ -68,22 +68,103 @@ describe('fd dup diagnostics', () => {
     server.close();
   });
 
-  it('alternative: dup via process.binding if /proc/self/fd fails', { timeout: 5000 }, async () => {
-    // Test whether we can use a different dup mechanism
-    try {
-      const binding = (process as any).binding('spawn_sync');
-      console.log('spawn_sync binding available:', !!binding);
-    } catch (e: any) {
-      console.log('spawn_sync binding not available:', e.message);
-    }
+  it('alternative: detach handle without closing fd', { timeout: 5000 }, async () => {
+    const { Worker } = await import('node:worker_threads');
 
-    // Check if native addon-free dup is possible via other means
-    try {
-      const { execSync } = await import('node:child_process');
-      const result = execSync('ls /proc/self/fd/ 2>&1 || echo "NO_PROC"', { encoding: 'utf8' });
-      console.log('/proc/self/fd listing:', result.trim().slice(0, 200));
-    } catch (e: any) {
-      console.log('ls /proc/self/fd failed:', e.message);
-    }
+    const workerCode = `
+      const { parentPort } = require('node:worker_threads');
+      const { Socket } = require('node:net');
+      parentPort.on('message', ({ fd }) => {
+        const sock = new Socket({ fd, readable: true, writable: true });
+        sock.setNoDelay(true);
+        sock.write('hello from detach\\n');
+        sock.end();
+      });
+    `;
+    const worker = new Worker(workerCode, { eval: true });
+
+    const server = createServer();
+    server.listen(0);
+    await once(server, 'listening');
+    const port = (server.address() as any).port;
+
+    server.on('connection', (socket: any) => {
+      const handle = socket._handle;
+      const fd: number = handle.fd;
+      // Stop libuv from reading on this fd
+      handle.readStop();
+      // Prevent socket.destroy() from closing the fd
+      handle.close = (cb: any) => {
+        if (cb) cb();
+      };
+      // Detach
+      socket._handle = null;
+      socket.destroy();
+      worker.postMessage({ fd });
+    });
+
+    const client = connect(port);
+    const chunks: Buffer[] = [];
+    client.on('data', (c: any) => chunks.push(Buffer.isBuffer(c) ? c : Buffer.from(c)));
+    await once(client, 'end');
+
+    const result = Buffer.concat(chunks).toString('utf8');
+    console.log('detach approach result:', JSON.stringify(result));
+    assert.equal(result, 'hello from detach\n');
+
+    server.close();
+    await worker.terminate();
+  });
+
+  it('alternative: detach handle with bidirectional HTTP', { timeout: 10000 }, async () => {
+    const { Worker } = await import('node:worker_threads');
+    const http = await import('node:http');
+
+    const workerCode = `
+      const { parentPort } = require('node:worker_threads');
+      const net = require('net');
+      const http = require('http');
+      const srv = http.createServer((req, res) => { res.end('bidi-ok'); });
+      parentPort.on('message', ({ fd }) => {
+        const sock = new net.Socket({ fd, readable: true, writable: true });
+        sock.setNoDelay(true);
+        srv.emit('connection', sock);
+      });
+    `;
+    const worker = new Worker(workerCode, { eval: true });
+
+    const server = createServer();
+    server.listen(0);
+    await once(server, 'listening');
+    const port = (server.address() as any).port;
+
+    server.on('connection', (socket: any) => {
+      const handle = socket._handle;
+      const fd: number = handle.fd;
+      handle.readStop();
+      handle.close = (cb: any) => {
+        if (cb) cb();
+      };
+      socket._handle = null;
+      socket.destroy();
+      worker.postMessage({ fd });
+    });
+
+    // Full HTTP roundtrip
+    const body = await new Promise<string>((resolve, reject) => {
+      const req = http.request({ host: '127.0.0.1', port, path: '/' }, (res) => {
+        const chunks: Buffer[] = [];
+        res.on('data', (c: any) => chunks.push(Buffer.isBuffer(c) ? c : Buffer.from(c)));
+        res.on('end', () => resolve(Buffer.concat(chunks).toString('utf8')));
+      });
+      req.on('error', reject);
+      req.end();
+    });
+
+    console.log('bidi HTTP result:', JSON.stringify(body));
+    assert.equal(body, 'bidi-ok');
+
+    server.close();
+    await worker.terminate();
   });
 });