diff --git a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime.cpp b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime.cpp
index 4e0885764..7196e9fc6 100644
--- a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime.cpp
+++ b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime.cpp
@@ -3735,14 +3735,7 @@ struct v8_dom_runtime::implementation final {
             v8::Function::New(local_context, structured_clone, {}, 1).ToLocalChecked()).Check();
         install_indexeddb(local_context);
         install_performance_timeline(local_context);
-        auto worker_constructor=v8::Function::New(local_context, worker_construct, {}, 1).ToLocalChecked();
-        v8::Local<v8::Value> event_target,worker_prototype,event_prototype;
-        if(local_context->Global()->Get(local_context,js_string(isolate,"EventTarget")).ToLocal(&event_target)
-            &&event_target->IsFunction()
-            &&worker_constructor->Get(local_context,js_string(isolate,"prototype")).ToLocal(&worker_prototype)
-            &&event_target.As<v8::Object>()->Get(local_context,js_string(isolate,"prototype")).ToLocal(&event_prototype))
-            worker_prototype.As<v8::Object>()->SetPrototype(local_context,event_prototype).FromMaybe(false);
-        local_context->Global()->Set(local_context, js_string(isolate, "Worker"),worker_constructor).Check();
+        install_worker_constructor(local_context);
         install_clipboard_api(local_context);
         install_websocket_globals(local_context);
         install_editor_web_platform_globals(local_context);
diff --git a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_cache_and_frames.inc b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_cache_and_frames.inc
index d8412d76b..965bfa763 100644
--- a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_cache_and_frames.inc
+++ b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_cache_and_frames.inc
@@ -1903,6 +1903,7 @@
         install_websocket_globals(local_context);
         install_editor_web_platform_globals(local_context);
         install_message_channel(local_context);
+        install_worker_constructor(local_context);
         install_tree_walker_platform(local_context);
         install_custom_elements_platform(local_context);
         install_fetch_globals(local_context);
diff --git a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_workers.inc b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_workers.inc
index 5b230a3f4..ef1f927cc 100644
--- a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_workers.inc
+++ b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_workers.inc
@@ -35,6 +35,35 @@
     static constexpr size_t maximum_worker_errors = 16U;
     static constexpr size_t maximum_worker_error_length = 4096U;
 
+    void install_worker_constructor(v8::Local<v8::Context> local_context) {
+        auto worker_constructor = v8::Function::New(
+            local_context,
+            worker_construct,
+            {},
+            1).ToLocalChecked();
+        v8::Local<v8::Value> event_target;
+        v8::Local<v8::Value> worker_prototype;
+        v8::Local<v8::Value> event_prototype;
+        if (local_context->Global()->Get(
+                local_context,
+                js_string(isolate, "EventTarget")).ToLocal(&event_target)
+            && event_target->IsFunction()
+            && worker_constructor->Get(
+                local_context,
+                js_string(isolate, "prototype")).ToLocal(&worker_prototype)
+            && event_target.As<v8::Object>()->Get(
+                local_context,
+                js_string(isolate, "prototype")).ToLocal(&event_prototype)) {
+            worker_prototype.As<v8::Object>()->SetPrototype(
+                local_context,
+                event_prototype).FromMaybe(false);
+        }
+        local_context->Global()->Set(
+            local_context,
+            js_string(isolate, "Worker"),
+            worker_constructor).Check();
+    }
+
     static v8::MaybeLocal<v8::Value> worker_transfer(
         const v8::FunctionCallbackInfo<v8::Value>& info) {
         if (info.Length() < 2) return v8::Undefined(info.GetIsolate());
@@ -337,6 +366,8 @@
                     auto realm=child->context.Get(child->isolate);v8::Context::Scope scope(realm);
                     if(packet&&!child->dispatch_worker_message(realm,realm->Global(),&*packet))report(child->last_error);
                     child->drain_tasks();
+                    child->perform_microtask_checkpoint();
+                    if (!child->promote_pending_promise_error()) report(child->last_error);
                 }
                 {std::lock_guard lock(raw->mutex);raw->running_isolate=nullptr;}
                 child->isolate->CancelTerminateExecution();
diff --git a/experiments/WebScene.NativeEngine.Probe/tests/hybrid_v8_runtime_tests.cpp b/experiments/WebScene.NativeEngine.Probe/tests/hybrid_v8_runtime_tests.cpp
index 6b5273dc8..abd7096ad 100644
--- a/experiments/WebScene.NativeEngine.Probe/tests/hybrid_v8_runtime_tests.cpp
+++ b/experiments/WebScene.NativeEngine.Probe/tests/hybrid_v8_runtime_tests.cpp
@@ -218,6 +218,9 @@ void test_iframe_worker_extension_host_port_bootstrap() {
       const child = frame.contentDocument;
       child.open();
       child.write(`<!doctype html><script>
+        if (typeof Worker !== 'function') {
+          throw Error('Worker is not installed in the iframe realm');
+        }
         onmessage = event => {
           if (event.origin !== origin || !(event.data.port instanceof MessagePort)
               || !(event.data.port instanceof EventTarget)
diff --git a/experiments/WebScene.NativeEngine.Probe/tests/native_v8_runtime_inspector_tests.inc b/experiments/WebScene.NativeEngine.Probe/tests/native_v8_runtime_inspector_tests.inc
index 8082836f9..7fdf0097e 100644
--- a/experiments/WebScene.NativeEngine.Probe/tests/native_v8_runtime_inspector_tests.inc
+++ b/experiments/WebScene.NativeEngine.Probe/tests/native_v8_runtime_inspector_tests.inc
@@ -1126,14 +1126,14 @@ void test_v8_inspector_raw_cdp_session(webscene_engine* engine)
         session_id,
         std::string{"{\"id\":650,\"method\":\"Runtime.evaluate\",\"params\":{\"contextId\":"}
             + std::to_string(frame_context_id)
-            + R"(,"expression":"parent.__websceneDetachedFrameCallbacks = 0; const record = () => ++parent.__websceneDetachedFrameCallbacks; setTimeout(record, 100); setInterval(record, 100); requestAnimationFrame(record); const originalTimeout = globalThis.setTimeout; globalThis.setTimeout = callback => originalTimeout(callback, 100); const channel = new MessageChannel(); channel.port1.onmessage = record; channel.port2.postMessage('queued'); globalThis.setTimeout = originalTimeout;","returnByValue":true}})" );
+            + R"(,"expression":"parent.__websceneDetachedFrameCallbacks = 0; parent.__websceneInspectorFrameDetached = false; const record = () => { if (parent.__websceneInspectorFrameDetached) ++parent.__websceneDetachedFrameCallbacks; }; setTimeout(record, 100); setInterval(record, 100); requestAnimationFrame(record); const originalTimeout = globalThis.setTimeout; globalThis.setTimeout = callback => originalTimeout(callback, 100); const channel = new MessageChannel(); channel.port1.onmessage = record; channel.port2.postMessage('queued'); globalThis.setTimeout = originalTimeout;","returnByValue":true}})" );
     require(
         wait_for_inspector_message(messages, R"("id":650)"),
         "Inspector could not schedule detached-frame task fixtures");
     dispatch_inspector_test_message(
         engine,
         session_id,
-        R"({"id":66,"method":"Runtime.evaluate","params":{"expression":"document.body.removeChild(globalThis.__inspectorLifecycleFrame); delete globalThis.__inspectorLifecycleFrame;","returnByValue":true}})");
+        R"({"id":66,"method":"Runtime.evaluate","params":{"expression":"globalThis.__websceneInspectorFrameDetached = true; document.body.removeChild(globalThis.__inspectorLifecycleFrame); delete globalThis.__inspectorLifecycleFrame;","returnByValue":true}})");
     require(
         wait_for_inspector_message(messages, R"("id":66)"),
         "Inspector iframe removal did not complete");
diff --git a/tests/WebPlatformSubset/contracts/iframe-worker-extension-host.html b/tests/WebPlatformSubset/contracts/iframe-worker-extension-host.html
new file mode 100644
index 000000000..8b2cc44c8
--- /dev/null
+++ b/tests/WebPlatformSubset/contracts/iframe-worker-extension-host.html
@@ -0,0 +1,73 @@
+<!doctype html>
+<title>Iframe extension host creates a module Worker</title>
+<script>
+window.__webSceneWptState = {complete:false,harness:null,results:[],errors:[],diagnostics:[]};
+window.record = (name, condition) => __webSceneWptState.results.push({
+  name,status:condition?'PASS':'FAIL',message:condition?null:'Contract failed',stack:null
+});
+window.finish = () => {
+  const s=__webSceneWptState;
+  s.harness={status:s.results.some(r=>r.status!=='PASS')?1:0,message:null,stack:null};
+  s.complete=true;
+};
+
+addEventListener('message', event => {
+  if (event.data && event.data.type === 'worker-error') {
+    __webSceneWptState.errors.push(event.data.message);
+    record('Iframe-created module Worker completed without errors', false);
+    finish();
+    return;
+  }
+  if (event.data && event.data.type === 'worker-started') {
+    record('Iframe-created module Worker starts in its isolated realm', true);
+    return;
+  }
+  if (event.data !== 'vscode.bootstrap.nls') return;
+  const frame = document.querySelector('iframe');
+  record('Extension-host iframe preserves source Window identity',
+    event.source === frame.contentWindow);
+  record('Extension-host iframe uses the parent origin', event.origin === origin);
+  const channel = new MessageChannel();
+  channel.port1.onmessage = response => {
+    record('Iframe-created module Worker bridges its transferred port', response.data === 42);
+    channel.port1.close();
+    finish();
+  };
+  event.source.postMessage(
+    {type:'vscode.init', port:channel.port2}, origin, [channel.port2]);
+  channel.port1.postMessage(41);
+});
+
+try {
+  const frame = document.createElement('iframe');
+  document.body.appendChild(frame);
+  const child = frame.contentDocument;
+  child.open();
+  child.write(`<script>
+    const workerModuleUrl = new URL(
+      './resources/aureon/iframe-worker-extension-host-module.js', location.href).href;
+    const source = \`await import(\${JSON.stringify(workerModuleUrl)});\`;
+    const blob = new Blob([source], {type:'application/javascript'});
+    const worker = new Worker(URL.createObjectURL(blob), {
+      name:'LocalWebWorker', type:'module'
+    });
+    if (!(worker instanceof Worker) || !(worker instanceof EventTarget))
+      throw Error('iframe Worker interface identity changed');
+    worker.onerror = event => parent.postMessage({
+      type:'worker-error', message:event.message
+    }, '*');
+    worker.onmessage = event => {
+      if (event.data === 'worker-started') {
+        parent.postMessage({type:'worker-started'}, '*');
+      }
+    };
+    onmessage = event => worker.postMessage(event.data, event.ports);
+    parent.postMessage('vscode.bootstrap.nls', '*');
+  <\/script>`);
+  child.close();
+} catch (error) {
+  __webSceneWptState.errors.push(String(error));
+  record('Iframe extension-host Worker bootstrap completed', false);
+  finish();
+}
+</script>
diff --git a/tests/WebPlatformSubset/contracts/resources/aureon/iframe-worker-extension-host-module.js b/tests/WebPlatformSubset/contracts/resources/aureon/iframe-worker-extension-host-module.js
new file mode 100644
index 000000000..a61ce3148
--- /dev/null
+++ b/tests/WebPlatformSubset/contracts/resources/aureon/iframe-worker-extension-host-module.js
@@ -0,0 +1,7 @@
+postMessage('worker-started');
+self.onmessage = event => {
+  const port = event.data.port;
+  if (!(port instanceof MessagePort)) throw Error('worker port transfer failed');
+  port.onmessage = message => port.postMessage(message.data + 1);
+  port.start();
+};
diff --git a/tests/WebPlatformSubset/webscene-aureon-runtime-profile.json b/tests/WebPlatformSubset/webscene-aureon-runtime-profile.json
index 37a6744b2..c04ec0854 100644
--- a/tests/WebPlatformSubset/webscene-aureon-runtime-profile.json
+++ b/tests/WebPlatformSubset/webscene-aureon-runtime-profile.json
@@ -44,6 +44,17 @@
       "reason": "Focused Code OSS iframe bootstrap candidate matching the extension-host MessagePort handoff.",
       "nativeNavigation": true
     },
+    {
+      "path": "contracts/iframe-worker-extension-host.html",
+      "type": "contract",
+      "capabilities": [
+        "iframe-worker-constructor",
+        "module-workers",
+        "messageport-transfer"
+      ],
+      "reason": "Code OSS-shaped regression proving its hydrated extension-host iframe can construct a module Worker and bridge the transferred bootstrap port.",
+      "nativeNavigation": true
+    },
     {
       "path": "contracts/worker-termination-queue-messageerror.html",
       "type": "contract",