diff --git a/plugins/codex/scripts/lib/broker-lifecycle.mjs b/plugins/codex/scripts/lib/broker-lifecycle.mjs
index ef763819..4e214c40 100644
--- a/plugins/codex/scripts/lib/broker-lifecycle.mjs
+++ b/plugins/codex/scripts/lib/broker-lifecycle.mjs
@@ -56,12 +56,13 @@ export async function sendBrokerShutdown(endpoint) {
   });
 }
 
-export function spawnBrokerProcess({ scriptPath, cwd, endpoint, pidFile, logFile, env = process.env }) {
+export function spawnBrokerProcess({ scriptPath, cwd, endpoint, pidFile, logFile, env = process.env, spawnImpl = spawn }) {
   const logFd = fs.openSync(logFile, "a");
-  const child = spawn(process.execPath, [scriptPath, "serve", "--endpoint", endpoint, "--cwd", cwd, "--pid-file", pidFile], {
+  const child = spawnImpl(process.execPath, [scriptPath, "serve", "--endpoint", endpoint, "--cwd", cwd, "--pid-file", pidFile], {
     cwd,
     env,
     detached: true,
+    windowsHide: true,
     stdio: ["ignore", logFd, logFd]
   });
   child.unref();
diff --git a/tests/broker-lifecycle.test.mjs b/tests/broker-lifecycle.test.mjs
new file mode 100644
index 00000000..5e6e76a7
--- /dev/null
+++ b/tests/broker-lifecycle.test.mjs
@@ -0,0 +1,50 @@
+import path from "node:path";
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { spawnBrokerProcess } from "../plugins/codex/scripts/lib/broker-lifecycle.mjs";
+import { makeTempDir } from "./helpers.mjs";
+
+test("spawnBrokerProcess hides detached broker windows on Windows", () => {
+  const cwd = makeTempDir();
+  const logFile = path.join(cwd, "broker.log");
+  const pidFile = path.join(cwd, "broker.pid");
+  let captured = null;
+  let unrefCalled = false;
+
+  const child = spawnBrokerProcess({
+    scriptPath: path.join(cwd, "app-server-broker.mjs"),
+    cwd,
+    endpoint: "unix:/tmp/broker.sock",
+    pidFile,
+    logFile,
+    env: { PATH: "/bin" },
+    spawnImpl(command, args, options) {
+      captured = { command, args, options };
+      return {
+        pid: 1234,
+        unref() {
+          unrefCalled = true;
+        }
+      };
+    }
+  });
+
+  assert.equal(child.pid, 1234);
+  assert.equal(unrefCalled, true);
+  assert.equal(captured.options.cwd, cwd);
+  assert.equal(captured.options.detached, true);
+  assert.equal(captured.options.windowsHide, true);
+  assert.deepEqual(captured.options.env, { PATH: "/bin" });
+  assert.deepEqual(captured.options.stdio.slice(0, 1), ["ignore"]);
+  assert.deepEqual(captured.args, [
+    path.join(cwd, "app-server-broker.mjs"),
+    "serve",
+    "--endpoint",
+    "unix:/tmp/broker.sock",
+    "--cwd",
+    cwd,
+    "--pid-file",
+    pidFile
+  ]);
+});