diff --git a/apps/ai-game-creator-shell/src/features/project-workspace/modelAvailabilityCopy.ts b/apps/ai-game-creator-shell/src/features/project-workspace/modelAvailabilityCopy.ts
index c37cdd28a..b8135de01 100644
--- a/apps/ai-game-creator-shell/src/features/project-workspace/modelAvailabilityCopy.ts
+++ b/apps/ai-game-creator-shell/src/features/project-workspace/modelAvailabilityCopy.ts
@@ -1,21 +1,34 @@
 import type { ClientLlmModelUnavailableReason } from '../../services/llmModelCatalog';
 
 /**
- * 锁定项 hover / 键盘 focus 的原因文案。
+ * 原因 → 文案的统一映射。
  *
- * `unknown` 是契约的前向兜底，后端将来新增 `reason` 时旧客户端仍给出可读文案。
+ * `unknown` 是契约的前向兜底，后端将来新增 `reason` 时旧客户端仍给出可读文案；两个 helper
+ * 共用本表，避免各自维护一份 switch 后漂移。
  */
+const REASON_COPY: Record<
+  ClientLlmModelUnavailableReason,
+  { label: string; fallback: string }
+> = {
+  plan_required: {
+    label: '订阅计划不支持',
+    fallback: '所选模型需要更高订阅计划，已切换为默认模型',
+  },
+  disabled: {
+    label: '该模型已下线',
+    fallback: '所选模型已下线，已切换为默认模型',
+  },
+  unknown: {
+    label: '暂不可用',
+    fallback: '所选模型已不可用，已切回默认模型',
+  },
+};
+
+/** 锁定项 hover / 键盘 focus 的原因文案。 */
 export function unavailableModelReasonLabel(
   reason: ClientLlmModelUnavailableReason,
 ): string {
-  switch (reason) {
-    case 'plan_required':
-      return '订阅计划不支持';
-    case 'disabled':
-      return '该模型已下线';
-    default:
-      return '暂不可用';
-  }
+  return (REASON_COPY[reason] ?? REASON_COPY.unknown).label;
 }
 
 /**
@@ -27,12 +40,8 @@ export function unavailableModelReasonLabel(
 export function unavailableModelFallbackNotice(
   unavailableReason: ClientLlmModelUnavailableReason | undefined,
 ): string {
-  switch (unavailableReason) {
-    case 'plan_required':
-      return '所选模型需要更高订阅计划，已切换为默认模型';
-    case 'disabled':
-      return '所选模型已下线，已切换为默认模型';
-    default:
-      return '所选模型已不可用，已切回默认模型';
+  if (!unavailableReason) {
+    return REASON_COPY.unknown.fallback;
   }
+  return (REASON_COPY[unavailableReason] ?? REASON_COPY.unknown).fallback;
 }