diff --git a/backend/app/services/kline_sync.py b/backend/app/services/kline_sync.py
index 85dd9558..c15c2d64 100644
--- a/backend/app/services/kline_sync.py
+++ b/backend/app/services/kline_sync.py
@@ -301,6 +301,7 @@ def sync_and_persist_daily_batch(
     end_date: datetime | None = None,
     on_chunk_done: Callable[[int, int], None] | None = None,
     zero_row_out: list[str] | None = None,
+    failed_out: list[str] | None = None,
 ) -> int:
     """批量同步日 K 并落到 Parquet。返回写入的行数。
 
@@ -309,12 +310,17 @@ def sync_and_persist_daily_batch(
     zero_row_out: 可选出参。本轮实际入库 0 行的标的(含无法识别被跳过的裸符号、
                   上游 200 空 payload 的静默 0 行)按调用方原始写法追加进该 list,
                   供上层 fail-loud 展示, 不再"显示成功实则全空" (#302)。
+    failed_out: 可选出参。分块拉取失败(超时/异常)的标的, 供上层把单票失败
+                上浮为 stage_errors 而非静默当成功 (#514)。
     """
     seen: set[str] = set()
     failed_syms: list[str] = []
     skipped_bare: list[str] = []
 
     def _finalize(written: int) -> int:
+        if failed_out is not None and failed_syms:
+            # 单票失败上浮给调用方 (daily_pipeline 汇入 stage_errors, #514)
+            failed_out.extend(failed_syms)
         zero_full = [s for s in requested if s not in seen and s not in failed_syms]
         if zero_full or skipped_bare:
             zero = [orig_by_full.get(s, s) for s in zero_full] + skipped_bare
diff --git a/backend/tests/test_kline_sync_failed_out.py b/backend/tests/test_kline_sync_failed_out.py
new file mode 100644
index 00000000..5fc0cc5f
--- /dev/null
+++ b/backend/tests/test_kline_sync_failed_out.py
@@ -0,0 +1,47 @@
+"""回归: sync_and_persist_daily_batch 必须接受 failed_out 并透出失败标的。
+
+daily_pipeline (#514) 的修复/定向分支传 failed_out=repair_failed_symbols,
+但本函数签名漏接该参数 → TypeError, 数据修正/boot 自检修复路径必炸
+(v0.3.21/v0.3.22 用户同步失败截图: "got an unexpected keyword argument
+'failed_out'")。
+"""
+from __future__ import annotations
+
+from types import SimpleNamespace
+
+import polars as pl
+import pytest
+
+from app.services import kline_sync
+from app.tickflow.repository import DataStore, KlineRepository
+
+
+@pytest.fixture
+def repo(tmp_path):
+    return KlineRepository(DataStore(tmp_path))
+
+
+def test_accepts_failed_out_and_surfaces_failed_symbols(monkeypatch, repo):
+    def fake_sync_daily_batch(symbols, **kwargs):
+        # 模拟分块拉取失败: 内部经由 failed_out 出参上报失败标的
+        kwargs["failed_out"].extend(["600519.SH", "000001.SZ"])
+        return pl.DataFrame()
+
+    monkeypatch.setattr(kline_sync, "sync_daily_batch", fake_sync_daily_batch)
+    capset = SimpleNamespace(has=lambda cap: True, limits=lambda cap: None)
+    failed: list[str] = []
+
+    written = kline_sync.sync_and_persist_daily_batch(
+        ["600519.SH", "000001.SZ"], repo, capset, failed_out=failed)
+
+    assert written == 0
+    assert failed == ["600519.SH", "000001.SZ"]
+
+
+def test_failed_out_omitted_still_works(monkeypatch, repo):
+    monkeypatch.setattr(
+        kline_sync, "sync_daily_batch", lambda symbols, **kw: pl.DataFrame())
+    capset = SimpleNamespace(has=lambda cap: True, limits=lambda cap: None)
+
+    assert kline_sync.sync_and_persist_daily_batch(
+        ["600519.SH"], repo, capset) == 0