diff --git a/packages/coding-agent/test/terminal-output-worker-client.test.ts b/packages/coding-agent/test/terminal-output-worker-client.test.ts
index 781aa4914..584fce6ad 100644
--- a/packages/coding-agent/test/terminal-output-worker-client.test.ts
+++ b/packages/coding-agent/test/terminal-output-worker-client.test.ts
@@ -10,7 +10,8 @@ class CleanExitWorker extends EventTarget {
 }
 
 test("legacy replay rejects when its worker exits before responding", async () => {
-	const originalWorker = globalThis.Worker;
+	const originalWorkerDescriptor = Object.getOwnPropertyDescriptor(globalThis, "Worker");
+	expect(originalWorkerDescriptor).toBeDefined();
 	Object.defineProperty(globalThis, "Worker", { configurable: true, value: CleanExitWorker });
 	try {
 		let outcome: { error?: unknown; settled: boolean } = { settled: false };
@@ -29,6 +30,11 @@ test("legacy replay rejects when its worker exits before responding", async () =
 		expect(outcome.error).toBeInstanceOf(Error);
 		expect((outcome.error as Error).message).toBe("Terminal output worker exited before responding");
 	} finally {
-		Object.defineProperty(globalThis, "Worker", { configurable: true, value: originalWorker });
+		if (originalWorkerDescriptor) {
+			Object.defineProperty(globalThis, "Worker", originalWorkerDescriptor);
+		} else {
+			Reflect.deleteProperty(globalThis, "Worker");
+		}
 	}
+	expect(Object.getOwnPropertyDescriptor(globalThis, "Worker")).toEqual(originalWorkerDescriptor);
 });
diff --git a/packages/coding-agent/test/tools/hub/launch-compat.test.ts b/packages/coding-agent/test/tools/hub/launch-compat.test.ts
index 822b2a348..ef004bf00 100644
--- a/packages/coding-agent/test/tools/hub/launch-compat.test.ts
+++ b/packages/coding-agent/test/tools/hub/launch-compat.test.ts
@@ -64,7 +64,8 @@ describe("launch broker protocol compatibility", () => {
 		} satisfies DaemonBrokerClient;
 		vi.spyOn(daemonClient, "daemonClientForProject").mockResolvedValue(client);
 
-		const originalWorker = globalThis.Worker;
+		const originalWorkerDescriptor = Object.getOwnPropertyDescriptor(globalThis, "Worker");
+		expect(originalWorkerDescriptor).toBeDefined();
 		Object.defineProperty(globalThis, "Worker", { configurable: true, value: CleanExitWorker });
 		try {
 			const result = await executeLaunch({ cwd: projectDir } as ToolSession, {
@@ -76,7 +77,12 @@ describe("launch broker protocol compatibility", () => {
 			expect(result.content).toEqual([{ type: "text", text: "ready\n[web: running; cursor=42]" }]);
 			expect(result.details?.terminalRows).toBeUndefined();
 		} finally {
-			Object.defineProperty(globalThis, "Worker", { configurable: true, value: originalWorker });
+			if (originalWorkerDescriptor) {
+				Object.defineProperty(globalThis, "Worker", originalWorkerDescriptor);
+			} else {
+				Reflect.deleteProperty(globalThis, "Worker");
+			}
 		}
+		expect(Object.getOwnPropertyDescriptor(globalThis, "Worker")).toEqual(originalWorkerDescriptor);
 	});
 });