diff --git a/app/service/config_release_service.py b/app/service/config_release_service.py
index 221f53c..be6da76 100644
--- a/app/service/config_release_service.py
+++ b/app/service/config_release_service.py
@@ -1,3 +1,4 @@
+import logging
 from datetime import UTC, datetime
 from uuid import uuid4
 
@@ -8,6 +9,8 @@ from app.model.audit import InteractionAudit
 from app.model.configuration import ConfigRelease, PlatformConfigItem
 from app.model.platform import DomainEventOutbox
 
+logger = logging.getLogger(__name__)
+
 
 class ConfigReleaseError(ValueError):
     pass
@@ -45,6 +48,44 @@ class ConfigReleaseService:
         await self.session.flush()
         return release
 
+    async def _warn_dropped_items(
+        self, release: ConfigRelease, previous_active: list[ConfigRelease]
+    ) -> None:
+        """列出"旧版本有、新版本没有"的配置项——它们在激活后会静默失效。
+
+        `config_release` 是**整版本替换**语义：激活新版本后，旧版本的所有配置项都不再生效。
+        所以只要新版本漏了某一项，它就是**无声消失**的——工具白名单随之变成空集、相关
+        Agent 的工具被 fail-closed 拒掉，而现场表现只是"客服/风控什么都答不了"，
+        没人会想到是发布配置少了一条。
+
+        本项目已经两次靠"发布前手工继承"规避（客服与风控的发布脚本里各写了一遍继承逻辑），
+        这说明风险是真实且反复出现的。这里不阻断激活（有时确实是要撤下某项配置），
+        但把它显式写进日志，让运维事后能查到"是谁把它弄没的"。
+        """
+        if not previous_active:
+            return
+        rows = (await self.session.execute(
+            select(
+                PlatformConfigItem.namespace,
+                PlatformConfigItem.config_key,
+                PlatformConfigItem.release_id,
+            ).where(PlatformConfigItem.release_id.in_(
+                [previous.id for previous in previous_active] + [release.id]
+            ))
+        )).all()
+        new_keys = {(namespace, key) for namespace, key, rid in rows if rid == release.id}
+        for previous in previous_active:
+            old_keys = {(namespace, key) for namespace, key, rid in rows if rid == previous.id}
+            dropped = sorted(old_keys - new_keys)
+            if dropped:
+                logger.warning(
+                    "配置发布 %s 取代 %s：以下 %d 条配置项在新版本中不存在，激活后即失效 → %s",
+                    release.release_no,
+                    previous.release_no,
+                    len(dropped),
+                    [f"{namespace}/{key}" for namespace, key in dropped],
+                )
+
     async def activate(self, release_id: int, actor_id: int) -> ConfigRelease:
         release = await self._get(release_id)
         if release.status != "approved":
@@ -54,6 +95,8 @@ class ConfigReleaseService:
         )
         now = self._now()
         previous_active = [previous for previous in active if previous.id != release.id]
+        # 把"本次激活会让哪些配置项失效"显式记进日志，见 _warn_dropped_items 的说明。
+        await self._warn_dropped_items(release, previous_active)
         for previous in previous_active:
             previous.status = "superseded"
             previous.updated_at = now
diff --git a/tests/unit/service/test_config_release_dropped_items.py b/tests/unit/service/test_config_release_dropped_items.py
new file mode 100644
index 0000000..12d6c96
--- /dev/null
+++ b/tests/unit/service/test_config_release_dropped_items.py
@@ -0,0 +1,91 @@
+"""配置发布激活时的"配置项被静默丢掉"警告。
+
+**背景**：`config_release` 是**整版本替换**语义 —— 激活新版本后，旧版本的配置项全部不再
+生效。所以新版本只要漏了某项，它就是**无声消失**的：`agent_tools` 里的工具白名单一少，
+相关 Agent 的工具就被 fail-closed 拒掉，而现场表现只是"客服/风控什么都答不了"，
+没人会想到是发布配置少了一条。
+
+本项目已经两次靠"发布前手工继承"规避（客服与风控的发布脚本里各写了一遍继承逻辑），
+说明风险真实且反复出现。这里锁住：只要发生丢项，就必须在日志里点名。
+"""
+
+import logging
+from typing import Any, cast
+
+import pytest
+
+from app.service.config_release_service import ConfigReleaseService
+
+
+class _FakeResult:
+    def __init__(self, rows: list[tuple[Any, ...]]) -> None:
+        self._rows = rows
+
+    def all(self) -> list[tuple[Any, ...]]:
+        return self._rows
+
+
+class _FakeSession:
+    """只提供 `execute(...).all()`，因为被测方法只用到这一条路径。"""
+
+    def __init__(self, rows: list[tuple[Any, ...]]) -> None:
+        self._rows = rows
+
+    async def execute(self, statement: Any) -> _FakeResult:
+        return _FakeResult(self._rows)
+
+
+class _Release:
+    def __init__(self, release_id: int, release_no: str) -> None:
+        self.id = release_id
+        self.release_no = release_no
+
+
+def _service(rows: list[tuple[Any, ...]]) -> ConfigReleaseService:
+    return ConfigReleaseService(cast(Any, _FakeSession(rows)))
+
+
+@pytest.mark.asyncio
+async def test_warns_when_new_release_drops_config_items(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """新版本少了一条配置项时必须点名警告——它会静默失效。"""
+    service = _service([
+        ("agent_tools", "customer_service:faq", 1),        # 旧版本有
+        ("agent_tools", "risk:risk_overview", 2),          # 新版本新增
+    ])
+
+    with caplog.at_level(logging.WARNING):
+        await service._warn_dropped_items(_Release(2, "new"), [_Release(1, "old")])
+
+    assert "customer_service:faq" in caplog.text
+    assert "agent_tools/customer_service:faq" in caplog.text
+
+
+@pytest.mark.asyncio
+async def test_no_warning_when_everything_is_carried_over(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """配置项被完整继承时不该有噪音——否则运维会习惯性忽略这条日志。"""
+    service = _service([
+        ("agent_tools", "customer_service:faq", 1),
+        ("agent_tools", "customer_service:faq", 2),
+    ])
+
+    with caplog.at_level(logging.WARNING):
+        await service._warn_dropped_items(_Release(2, "new"), [_Release(1, "old")])
+
+    assert caplog.text == ""
+
+
+@pytest.mark.asyncio
+async def test_first_release_warns_about_nothing(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """平台首个版本没有"前一个版本"，不该报丢项。"""
+    service = _service([("agent_tools", "customer_service:faq", 1)])
+
+    with caplog.at_level(logging.WARNING):
+        await service._warn_dropped_items(_Release(1, "first"), [])
+
+    assert caplog.text == ""