feat(S2): max_tokens dynamic from template, remove hardcoded 500

- PromptTemplate model: add max_tokens (default 500) and example_input fields
- generate_with_llm: read max_tokens from template, accept override param
- api_prompt_generate: accept optional max_tokens with 100-4096 clamp
- Vue: add advanced options toggle with max_tokens input
- Vue: auto-populate max_tokens from selected template

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/flask_prompt_master/models/models.py

@@ -81,6 +81,8 @@ class PromptTemplate(db.Model):
     sub_category = db.Column(db.String(50))
     system_prompt = db.Column(db.Text, nullable=False)
     is_default = db.Column(db.Boolean, default=False)
+    max_tokens = db.Column(db.Integer, default=500)
+    example_input = db.Column(db.Text)
     created_at = db.Column(db.DateTime, default=datetime.utcnow)
 
 class MealPlan(db.Model):

src/flask_prompt_master/routes/routes.py

@@ -49,20 +49,28 @@ def get_system_prompt(template_id=None):
 
 请直接返回优化后的提示词，不要添加任何解释或其他内容。"""
 
-def generate_with_llm(input_text, template_id=None, max_retries=3):
+def generate_with_llm(input_text, template_id=None, max_retries=3, max_tokens=None):
     """调用大模型API生成提示词，带重试机制"""
     import time
-    
+
     system_prompt = get_system_prompt(template_id)
     start_time = time.time()  # 记录开始时间
-    
+
+    # 确定 max_tokens: 参数传入 > 模板配置 > 默认 500
+    _max_tokens = max_tokens or 500
+    if not max_tokens and template_id:
+        template = PromptTemplate.query.get(template_id)
+        if template and template.max_tokens:
+            _max_tokens = template.max_tokens
+
     # 记录参数到日志
     current_app.logger.info("=== API 调用参数 ===")
     current_app.logger.info(f"模板ID: {template_id}")
     current_app.logger.info(f"输入文本: {input_text}")
     current_app.logger.info(f"系统提示: {system_prompt}")
+    current_app.logger.info(f"max_tokens: {_max_tokens}")
     current_app.logger.info("==================")
-    
+
     for attempt in range(max_retries):
         try:
             response = client.chat.completions.create(
@@ -72,7 +80,7 @@ def generate_with_llm(input_text, template_id=None, max_retries=3):
                     {"role": "user", "content": input_text}
                 ],
                 temperature=0.7,
-                max_tokens=500,
+                max_tokens=_max_tokens,
                 timeout=60  # 设置60秒超时
             )
             
@@ -342,6 +350,7 @@ def get_templates_by_category(category):
             'profession': template.profession,
             'sub_category': template.sub_category,
             'system_prompt': template.system_prompt,
+            'max_tokens': template.max_tokens or 500,
             'sample_input': build_sample_input_text(template),
         }
         template_list.append(template_dict)
@@ -401,8 +410,18 @@ def api_prompt_generate():
     if len(input_text) > 1000:
         return jsonify({'success': False, 'message': '需求描述请勿超过 1000 字'}), 400
 
+    # 可选 max_tokens 覆盖
+    _mt = data.get('max_tokens')
+    _max_tokens = None
+    if _mt is not None and _mt != '':
+        try:
+            _max_tokens = int(_mt)
+            _max_tokens = max(100, min(4096, _max_tokens))
+        except (TypeError, ValueError):
+            pass
+
     try:
-        generated_text = generate_with_llm(input_text, template_id)
+        generated_text = generate_with_llm(input_text, template_id, max_tokens=_max_tokens)
         if not generated_text or (
             isinstance(generated_text, str) and generated_text.startswith('提示词生成失败')
         ):

vue-app/src/api/modules/prompt.ts

@@ -14,6 +14,6 @@ export function fetchTemplatesByCategory(category: string) {
   return client.get<TemplatesByCategoryResponse>(path).then((r) => r.data)
 }
 
-export function generatePrompt(body: { input_text: string; template_id: number | null }) {
+export function generatePrompt(body: { input_text: string; template_id: number | null; max_tokens?: number }) {
   return client.post<GeneratePromptResponse>('/api/prompt/generate', body).then((r) => r.data)
 }

vue-app/src/api/types/template.ts

@@ -7,6 +7,7 @@ export interface PromptTemplateItem {
   profession: string | null
   sub_category: string | null
   system_prompt: string
+  max_tokens: number
   sample_input: string
 }
 

vue-app/src/views/GenerateView.vue

@@ -26,6 +26,8 @@ const selectedTemplateId = ref<number | undefined>(undefined)
 
 const inputText = ref('')
 const autoFillSample = ref(true)
+const showAdvanced = ref(false)
+const maxTokensOverride = ref<number | undefined>(undefined)
 
 const result = ref<{ id: number; input_text: string; generated_text: string } | null>(null)
 
@@ -100,9 +102,11 @@ watch(filteredTemplates, (list) => {
 })
 
 watch(selectedTemplateId, (id) => {
-  if (!autoFillSample.value || id == null) return
-  const t = templates.value.find((x) => x.id === id)
-  if (t?.sample_input) inputText.value = t.sample_input
+  if (id != null) {
+    const t = templates.value.find((x) => x.id === id)
+    if (autoFillSample.value && t?.sample_input) inputText.value = t.sample_input
+    maxTokensOverride.value = t?.max_tokens || undefined
+  }
 })
 
 async function loadMeta() {
@@ -201,6 +205,7 @@ async function onSubmit() {
     const res = await generatePrompt({
       input_text: text,
       template_id: selectedTemplateId.value,
+      max_tokens: maxTokensOverride.value,
     })
     if (!res.success) {
       ElMessage.error(res.message || '生成失败')
@@ -356,9 +361,27 @@ onMounted(async () => {
         placeholder="请描述目标、背景、约束与期望输出…"
       />
       <div class="actions">
-        <el-button type="primary" size="large" :loading="generating" @click="onSubmit">
-          生成专业提示词
-        </el-button>
+        <el-space>
+          <el-button type="primary" size="large" :loading="generating" @click="onSubmit">
+            生成专业提示词
+          </el-button>
+          <el-button text type="info" @click="showAdvanced = !showAdvanced">
+            {{ showAdvanced ? '收起' : '高级选项' }}
+          </el-button>
+        </el-space>
+      </div>
+      <div v-if="showAdvanced" class="advanced-options">
+        <el-form-item label="输出长度 (tokens)" label-width="140px">
+          <el-input-number
+            v-model="maxTokensOverride"
+            :min="100"
+            :max="4096"
+            :step="100"
+            placeholder="由模板决定"
+            style="width: 220px"
+          />
+          <span class="hint">留空由模板决定，范围 100–4096</span>
+        </el-form-item>
       </div>
     </el-card>