diff --git a/src/container-lifecycle-state.test.ts b/src/container-lifecycle-state.test.ts
new file mode 100644
index 000000000..a1a644fb3
--- /dev/null
+++ b/src/container-lifecycle-state.test.ts
@@ -0,0 +1,16 @@
+import { markAgentExternallyKilled, isAgentExternallyKilled } from './container-lifecycle-state';
+import { containerLifecycleTestHelpers } from './container-lifecycle.test-utils';
+
+describe('container-lifecycle-state', () => {
+  beforeEach(() => {
+    containerLifecycleTestHelpers.resetAgentExternallyKilled();
+  });
+
+  it('resets externally-killed state via test helpers', () => {
+    expect(isAgentExternallyKilled()).toBe(false);
+    markAgentExternallyKilled();
+    expect(isAgentExternallyKilled()).toBe(true);
+    containerLifecycleTestHelpers.resetAgentExternallyKilled();
+    expect(isAgentExternallyKilled()).toBe(false);
+  });
+});
diff --git a/src/container-lifecycle-state.ts b/src/container-lifecycle-state.ts
index 4f5c0a1ae..4d274d592 100644
--- a/src/container-lifecycle-state.ts
+++ b/src/container-lifecycle-state.ts
@@ -8,10 +8,12 @@ export function isAgentExternallyKilled(): boolean {
   return agentExternallyKilled;
 }
 
-/**
- * Internal test-only reset helper.
- * Do not use in production flows.
- */
-export function resetAgentExternallyKilled(): void {
+function resetAgentExternallyKilled(): void {
   agentExternallyKilled = false;
 }
+
+/**
+ * @internal Exposed only for unit tests — not part of the public API.
+ */
+// ts-prune-ignore-next
+export const containerLifecycleStateTestHelpers = { resetAgentExternallyKilled };
diff --git a/src/container-lifecycle.test-utils.ts b/src/container-lifecycle.test-utils.ts
index 12a69c157..36546bb51 100644
--- a/src/container-lifecycle.test-utils.ts
+++ b/src/container-lifecycle.test-utils.ts
@@ -2,9 +2,9 @@
  * Test-only access to container lifecycle state helpers.
  * Tests should import from this file, not from production modules.
  */
-import { isAgentExternallyKilled, resetAgentExternallyKilled } from './container-lifecycle-state';
+import { containerLifecycleStateTestHelpers, isAgentExternallyKilled } from './container-lifecycle-state';
 
 export const containerLifecycleTestHelpers = {
   isAgentExternallyKilled,
-  resetAgentExternallyKilled,
+  resetAgentExternallyKilled: containerLifecycleStateTestHelpers.resetAgentExternallyKilled,
 };