diff --git a/apps/ai-game-creator-shell/src/features/agent-runtime/panels.tsx b/apps/ai-game-creator-shell/src/features/agent-runtime/panels.tsx
index 02ab29137..040b0b0dc 100644
--- a/apps/ai-game-creator-shell/src/features/agent-runtime/panels.tsx
+++ b/apps/ai-game-creator-shell/src/features/agent-runtime/panels.tsx
@@ -251,12 +251,15 @@ export function AgentRuntimeUserInputCard({
               placeholder="填写其他答案"
               rows={2}
               value={answer}
-              onChange={(event) =>
+              onChange={(event) => {
+                // React 会在事件派发结束后把 currentTarget 置空，而 setState 的
+                // updater 要等到渲染阶段才跑，所以必须在这里先取出值。
+                const { value } = event.currentTarget;
                 setAnswers((current) => ({
                   ...current,
-                  [question.id]: event.currentTarget.value,
-                }))
-              }
+                  [question.id]: value,
+                }));
+              }}
             />
           </fieldset>
         );
diff --git a/apps/ai-game-creator-shell/tests/agentRuntimeUserInputCard.test.tsx b/apps/ai-game-creator-shell/tests/agentRuntimeUserInputCard.test.tsx
new file mode 100644
index 000000000..cc53b7efb
--- /dev/null
+++ b/apps/ai-game-creator-shell/tests/agentRuntimeUserInputCard.test.tsx
@@ -0,0 +1,74 @@
+// @vitest-environment jsdom
+
+import { fireEvent, render, screen } from '@testing-library/react';
+import { StrictMode } from 'react';
+import { describe, expect, it } from 'vitest';
+
+import type { AgentRuntimeUserInputRequest } from '../src/app/types';
+import { AgentRuntimeUserInputCard } from '../src/features/agent-runtime/panels';
+
+function clarificationRequest(): AgentRuntimeUserInputRequest {
+  return {
+    schemaVersion: 'agc.user_input_request.v1',
+    requestId: 'req-1',
+    agentId: 'project-supervisor',
+    taskId: 'task-1',
+    sessionId: 'session-1',
+    runId: 'run-1',
+    actionId: 'action-1',
+    status: 'pending',
+    questions: [
+      {
+        id: 'q1',
+        header: '第1轮·关键决定',
+        question: '这局游戏的重玩动力是什么？',
+        options: [
+          { label: '分数驱动', description: '刷新纪录后重开' },
+          { label: '成长驱动', description: '解锁新能力后重开' },
+        ],
+      },
+    ],
+    allowFreeform: true,
+    responseId: null,
+    requestedAt: 1,
+    updatedAt: 1,
+  };
+}
+
+describe('AgentRuntimeUserInputCard 澄清输入', () => {
+  it('手动输入自由回答不会让页面崩溃', () => {
+    render(
+      <StrictMode>
+        <AgentRuntimeUserInputCard
+          request={clarificationRequest()}
+          controlBusy={false}
+        />
+      </StrictMode>,
+    );
+
+    const textarea = screen.getByLabelText('第1轮·关键决定 其他回答');
+    fireEvent.change(textarea, { target: { value: '玩家自己写的答案' } });
+
+    expect((textarea as HTMLTextAreaElement).value).toBe('玩家自己写的答案');
+  });
+
+  it('先选中选项再清空填充文本不会让页面崩溃', () => {
+    render(
+      <StrictMode>
+        <AgentRuntimeUserInputCard
+          request={clarificationRequest()}
+          controlBusy={false}
+        />
+      </StrictMode>,
+    );
+
+    fireEvent.click(screen.getByText('分数驱动'));
+    const textarea = screen.getByLabelText(
+      '第1轮·关键决定 其他回答',
+    ) as HTMLTextAreaElement;
+    expect(textarea.value).toBe('分数驱动');
+
+    fireEvent.change(textarea, { target: { value: '' } });
+    expect(textarea.value).toBe('');
+  });
+});