diff --git a/apps/ai-game-creator-shell/src/view/project-development/chat/conversation/directThreadChat.ts b/apps/ai-game-creator-shell/src/view/project-development/chat/conversation/directThreadChat.ts
index 4b8250e28..aee4c8a08 100644
--- a/apps/ai-game-creator-shell/src/view/project-development/chat/conversation/directThreadChat.ts
+++ b/apps/ai-game-creator-shell/src/view/project-development/chat/conversation/directThreadChat.ts
@@ -344,16 +344,22 @@ export function reduceDirectThreadEvent(
       // 失败终态带 `failure` 载荷：先把它落成本轮最后一条说明条目，再和正常终态走同一个收口
       // 函数。载荷在、原因非空才算一条说明；空原因不补一条空气泡（终态照样收口）。
       const failure = event.failure;
-      const withNotice =
-        failure && failure.message.trim()
-          ? upsertLiveEntry(state, {
-              itemId: directTurnFailureItemId(eventUserItemId, eventAt),
-              kind: 'message',
-              role: 'assistant',
-              text: directTurnFailureNoticeText(failure.message),
-              at: eventAt,
-            })
-          : state;
+      // `message` 在生成类型里是必填 string，但跨 IPC 的载荷没有运行时校验：缺字段 / `null`
+      // 时直接 `.trim()` 会在 reducer 里抛错，把这一条订阅之后的全部事件一起打断。判据与兄弟
+      // 函数 `directTurnFailureNoticeText` 保持一致，都是"不是非空字符串就当没有原因"。
+      const failureText =
+        failure && typeof failure.message === 'string'
+          ? failure.message.trim()
+          : '';
+      const withNotice = failureText
+        ? upsertLiveEntry(state, {
+            itemId: directTurnFailureItemId(eventUserItemId, eventAt),
+            kind: 'message',
+            role: 'assistant',
+            text: directTurnFailureNoticeText(failureText),
+            at: eventAt,
+          })
+        : state;
       return finishDirectThreadTurn(withNotice, eventAt);
     }
     case 'item.delta':
diff --git a/apps/ai-game-creator-shell/tests/directThreadChat.test.ts b/apps/ai-game-creator-shell/tests/directThreadChat.test.ts
index f26a33c6d..6dd1ef409 100644
--- a/apps/ai-game-creator-shell/tests/directThreadChat.test.ts
+++ b/apps/ai-game-creator-shell/tests/directThreadChat.test.ts
@@ -417,6 +417,29 @@ describe('DirectProject 聊天 reducer', () => {
       expect(failed.history).toHaveLength(0);
     });
 
+    it('载荷的 message 缺失或为 null 时不抛错，按"没有原因"收口', () => {
+      // 跨 IPC 的载荷没有运行时校验：字段缺失 / `null` 都到得了 reducer。这里只要求
+      // "不抛错 + 不补空气泡"，终态照样收口——抛错会连带打断这条订阅之后的所有事件。
+      for (const message of [undefined, null]) {
+        const malformed = {
+          type: 'turn.completed',
+          status: 'failed',
+          at: 2_000,
+          failure: { kind: 'host-dropped', message },
+        } as unknown as DirectThreadEvent;
+        const failed = reduceDirectThreadEvents(emptyDirectThreadChatState(), [
+          withUserItemId(
+            event({ type: 'turn.started', at: 1_000 }),
+            'direct-codex:turn-1:user',
+          ),
+          malformed,
+        ]);
+        expect(failed.turnRunning).toBe(false);
+        expect(failed.turnEndedAt).toBe(2_000);
+        expect(failed.history).toHaveLength(0);
+      }
+    });
+
     it('没有身份时用事件时间派生说明身份，两轮失败不会合并成一条', () => {
       const first = reduceDirectThreadEvents(emptyDirectThreadChatState(), [
         event({ type: 'turn.started', at: 1_000 }),