diff --git a/backend/app/api/catalog.py b/backend/app/api/catalog.py
index f5a85a6b..0526ca13 100644
--- a/backend/app/api/catalog.py
+++ b/backend/app/api/catalog.py
@@ -226,14 +226,21 @@ async def _detail(session: AsyncSession, source: Any, table: str, entry: catalog
 
 
 async def _table_key(session: AsyncSession, source: Any, table: str) -> tuple[str, catalog.CatalogEntry | None]:
-    """路径里的表名 → 目录的键。表结构里有的按表结构的写法；表结构里没有、但还留着目录的也认（便于清理）。"""
+    """路径里的表名 → 目录的键。表结构里有的按表结构的写法；表结构里没有、但还留着目录的也认（便于清理）。都没有时 404，
+    说清是哪一种「不在」（_missing）。"""
     key = catalog.resolve_table_name(source.schema_cache, table)
     entry = await catalog.read_entry(session, source.id, key or table)
     if key is None and entry is None:
-        raise HTTPException(404, f"数据源中没有表 {table}，可能已被删除或尚未探查结构")
+        raise await _missing(session, source, table)
     return key or table, entry
 
 
+async def _missing(session: AsyncSession, source: Any, table: str) -> HTTPException:
+    """表结构里没有这张表的 404：表已不在、数据源里没有、在探查范围外、读不到结构、说不清，和 /schema、/catalog/search、
+    目录清单的 absent_reason 同一套（source_objects.absent_message）。"""
+    return HTTPException(404, await source_objects.absent_message(session, source, table))
+
+
 def _conflict(e: catalog.CatalogConflict) -> HTTPException:
     return HTTPException(409, str(e))
 
@@ -906,7 +913,7 @@ async def catalog_table_assistant(source_id: str, table: str, payload: Assistant
     row, source = await _resolved(session, source_id)
     key = catalog.resolve_table_name(source.schema_cache, table)
     if key is None:
-        raise HTTPException(404, f"数据源中没有表 {table}，可能已被删除或尚未探查结构")
+        raise await _missing(session, source, table)
     messages = [m.model_dump() for m in payload.messages]
     if problem := catalog_assistant.conversation_problem(messages):
         raise HTTPException(422, problem)
diff --git a/backend/app/data/catalog_review.py b/backend/app/data/catalog_review.py
index 43e27594..78eb3438 100644
--- a/backend/app/data/catalog_review.py
+++ b/backend/app/data/catalog_review.py
@@ -41,7 +41,7 @@ from typing import Any
 from sqlalchemy import func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.data import catalog
+from app.data import catalog, source_objects
 from app.db.models import Run
 
 #: 队列的筛选：全部、影响数字的项、名称和说明
@@ -346,7 +346,7 @@ async def review_batch(session: AsyncSession, source: Any, items: Iterable[Batch
         key = known[item.table_name]
         if key is None:
             results[i] = _result(item, ok=False, code=CODE_TABLE_MISSING,
-                                 error=f"数据源中没有表 {item.table_name}，可能已被删除或尚未探查结构")
+                                 error=await source_objects.absent_message(session, source, item.table_name))
             continue
         groups.setdefault(key, []).append(i)
     at = catalog.now_iso()
diff --git a/backend/app/data/source_objects.py b/backend/app/data/source_objects.py
index 058fc989..f367045b 100644
--- a/backend/app/data/source_objects.py
+++ b/backend/app/data/source_objects.py
@@ -825,6 +825,33 @@ async def absent_reasons(session: AsyncSession, row: Any, names: Iterable[str])
     return out
 
 
+#: 表结构里没有的表给人看的一句（接口的 404、批量审阅逐条的错误）：和界面的 CATALOG_ABSENT_TEXT、/schema 的说法
+#: （schema_view.absent_detail，给模型看）同一套「不在」。{table} 是点名的表
+ABSENT_MESSAGE = {
+    ABSENT_REMOVED: "数据源中已经没有表 {table}（已删除或改名）",
+    ABSENT_MISSING: "数据源中没有表 {table}（全库的对象清单里也没有）",
+    ABSENT_OUT_OF_SCOPE: ("表 {table} 在探查范围外：对象索引里有它，但没有读取结构。在数据源卡片的「探查范围」里加入它，"
+                          "或在数据目录的搜索框搜索它并「加入范围」"),
+    ABSENT_REFLECT_FAILED: "表 {table} 在探查范围内，但上次探查读不到它的结构（权限不够或对象有问题），修好后重新探查即可",
+    ABSENT_UNKNOWN: ("表 {table} 不在已探查的表里：升级前的探查只取了一部分表，无法判断它是否还在，请回到数据源卡片重新"
+                     "「探查结构」"),
+}
+#: 说不出是哪一种「不在」时（上传表格、记录表按版本走；没有对象索引、又没截断过的老缓存认不出名字是不是从来就没有）
+ABSENT_PLAIN = "数据源中没有表 {table}"
+
+
+async def absent_message(session: AsyncSession, row: Any, table: str) -> str:
+    """点名的表不在表结构里时给人看的一句（ABSENT_MESSAGE）。手工接入的源按 absent_reasons 说是哪一种；上传表格、记录表
+    的结构随版本走，只说没有（目录清单把它们记成 removed，是说「那一版里没有」，点名一个从来没有过的名字时说不得「已删除」）；
+    没有对象索引的老缓存同理：absent_reasons 对没截断的一律记 removed，名字写错了也会这样，只说没有。"""
+    if (getattr(row, "origin", None) or "manual") != "manual":
+        return ABSENT_PLAIN.format(table=table)
+    reason = (await absent_reasons(session, row, [table])).get(table)
+    if reason == ABSENT_REMOVED and not await has_index(session, row.id, index_schema(row)):
+        reason = None
+    return ABSENT_MESSAGE.get(reason or "", ABSENT_PLAIN).format(table=table)
+
+
 @dataclass(frozen=True)
 class OutsideObject:
     """对象索引里在、范围外的一个对象（助手检索、目录搜索用）。"""
@@ -1039,7 +1066,8 @@ async def delete_index(session: AsyncSession, source_id: str) -> None:
 
 
 __all__ = [
-    "ABSENT_MISSING", "ABSENT_OUT_OF_SCOPE", "ABSENT_REFLECT_FAILED", "ABSENT_REMOVED", "ABSENT_UNKNOWN", "ADD_LIMIT", "AddOutcome",
+    "ABSENT_MESSAGE", "ABSENT_MISSING", "ABSENT_OUT_OF_SCOPE", "ABSENT_PLAIN", "ABSENT_REFLECT_FAILED", "ABSENT_REMOVED",
+    "ABSENT_UNKNOWN", "ADD_LIMIT", "AddOutcome",
     "INDEX_LIMIT", "IndexResult", "IndexedObject", "OutsideObject", "REFLECT_BATCH", "RULES_MAX", "Reflected",
     "RefreshStats", "SCOPE_DEFAULT", "SCOPE_MAX", "SCOPE_OPTION", "SCOPE_REASONS", "ScopePlan", "ScopeRules", "Trail",
     "VIA_CATALOG", "VIA_LOOK", "VIA_SCHEMA_TOOL", "absent_reasons", "add_to_scope", "apply_scope",
diff --git a/backend/tests/test_catalog_schema_truncated.py b/backend/tests/test_catalog_schema_truncated.py
index f0c99435..e4a9ba70 100644
--- a/backend/tests/test_catalog_schema_truncated.py
+++ b/backend/tests/test_catalog_schema_truncated.py
@@ -157,3 +157,24 @@ def test_legacy_truncated_cache_still_does_not_deny():
                                                        "truncated": True, "total": 205})
     text = describe_table(row, "t300")
     assert "中没有" not in text and "只探查了" in text and "information_schema" in text
+
+
+async def test_catalog_detail_of_an_out_of_scope_table_says_so(client, wide):
+    """对象索引里有、在探查范围外的表：GET /catalog/{表} 的 404 说「在探查范围外」，和 /schema、/catalog/search 同一套「不在」
+    （下一轮验收：以前说「可能已被删除或尚未探查结构」）；表助手、批量审阅的同一个错误也一样。对象索引里也没有的说「没有
+    这张表」。"""
+    sid, _ = wide
+    r = await client.get(f"/api/datasources/{sid}/catalog/t200")
+    assert r.status_code == 404 and "探查范围外" in r.json()["detail"], r.text
+    assert "可能已被删除" not in r.json()["detail"]
+    found = (await client.get(f"/api/datasources/{sid}/catalog/search", params={"q": "t200"})).json()["items"]
+    assert [i["absent_reason"] for i in found if i["name"] == "t200"] in (["out_of_scope"], [None]), found
+    r = await client.post(f"/api/datasources/{sid}/catalog/t201/assistant", json={"messages": [
+        {"role": "user", "content": "这张表是干什么的"}]})
+    assert r.status_code == 404 and "探查范围外" in r.json()["detail"], r.text
+    r = await client.post(f"/api/datasources/{sid}/catalog/review/batch", json={"items": [
+        {"table_name": "t202", "path": "label", "action": "confirm", "if_version": 0}]})
+    [result] = r.json()["results"]
+    assert result["ok"] is False and "探查范围外" in result["error"], result
+    r = await client.get(f"/api/datasources/{sid}/catalog/no_such_table")
+    assert r.status_code == 404 and "没有表 no_such_table" in r.json()["detail"] and "探查范围外" not in r.json()["detail"]