diff --git a/backend/internal/service/v1.go b/backend/internal/service/v1.go
index 6f7c24b..96439c8 100644
--- a/backend/internal/service/v1.go
+++ b/backend/internal/service/v1.go
@@ -38,7 +38,7 @@ var (
 	ErrInvalidAPIKey       = errors.New("invalid api key")
 	ErrUnknownModel        = errors.New("unknown model")
 	ErrUnsupportedParams   = errors.New("unsupported or unpriced parameters for this model")
-	ErrPromptTooLong       = errors.New("prompt too long (max 2000 characters)")
+	ErrPromptTooLong       = errors.New("prompt too long (max 1500 characters)")
 	ErrInsufficientFunds   = errors.New("insufficient credits")
 	ErrGenerationPending   = errors.New("generation executor not implemented yet")
 	ErrProviderAuth        = errors.New("provider token invalid or expired")
@@ -61,7 +61,7 @@ var (
 
 // maxPromptRunes caps prompt length (counted as characters, so Chinese = 1),
 // matching the 画图台 counter. Enforced for both 画图台 and API-key calls.
-const maxPromptRunes = 2000
+const maxPromptRunes = 1500
 
 // maxReferenceImageBytes bounds a single decoded reference image. 8 MB
 // comfortably covers real photos/screenshots; anything larger is almost
diff --git a/frontend/src/views/PlaygroundView.vue b/frontend/src/views/PlaygroundView.vue
index fe47d92..5d14867 100644
--- a/frontend/src/views/PlaygroundView.vue
+++ b/frontend/src/views/PlaygroundView.vue
@@ -526,9 +526,9 @@ onUnmounted(() => {
       <div>
         <div class="flex items-center justify-between mb-1.5">
           <label class="block text-xs font-medium text-slate-500">提示词</label>
-          <span class="text-[11px] tabular-nums" :class="prompt.length >= 2000 ? 'text-rose-500' : 'text-slate-400'">{{ prompt.length }}/2000</span>
+          <span class="text-[11px] tabular-nums" :class="prompt.length >= 1500 ? 'text-rose-500' : 'text-slate-400'">{{ prompt.length }}/1500</span>
         </div>
-        <textarea v-model="prompt" rows="4" maxlength="2000" class="field resize-none disabled:opacity-60 disabled:cursor-not-allowed"
+        <textarea v-model="prompt" rows="4" maxlength="1500" class="field resize-none disabled:opacity-60 disabled:cursor-not-allowed"
                   placeholder="描述想要的画面…如：黄昏时分,金色麦田里奔跑的金毛猎犬,电影感"></textarea>
       </div>