diff --git a/pipeline_llm/gateway.py b/pipeline_llm/gateway.py
index b0114d5..12c2afb 100644
--- a/pipeline_llm/gateway.py
+++ b/pipeline_llm/gateway.py
@@ -295,8 +295,14 @@ async def _pick_candidate(sor, model: dict, pref: str):
             matched = {i for i, e in tagged if (e.get('protocol') or '').strip() == mproto}
             untagged = {i for i, e in enumerate(endpoints)
                         if not (e.get('protocol') or '').strip()}
-            usable = matched | untagged
-            if not matched:
+            # 有协议匹配端点 → 只选匹配的（同账号多端点余额同分，按序会选到
+            # 第一个即 compatible-mode → 404，必须排除不匹配项而非并集）；
+            # 无匹配但有未标注（历史）端点 → 兜底用未标注；全无 → 报错
+            if matched:
+                usable = matched
+            elif untagged:
+                usable = untagged
+            else:
                 return False, ('供应商端点均为其他协议（模型模板协议 %s，端点协议 %s）——'
                                '原生异步(openai_compat 之外)与兼容模式端点 base_url 不同，'
                                '混用必 404。请在供应商端点目录添加协议 %s 的端点'