diff --git a/CHANGELOG.md b/CHANGELOG.md
index 76096c8..1c77d67 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,8 +27,13 @@
   治理侧同步才补齐；只按 `term tenant_id` 过滤会把整库正文漏掉（真跑：索引有 2 条、
   导出 0 条、候选校验报 legacy coverage）。改为"本租户 或 未写租户"，写了别的租户仍排除。
 
+- **空目标索引不能当成"索引被改坏"**：全新 WeKnora 实例先用空映射建索引（`{}`），
+  字段等第一次写入才动态生成；首次同步因此在读取目标状态时就失败。现在"没有范围字段
+  + 确实 0 篇文档"按空基线处理，有文档却看不出归属仍然报错。
+
 ### Tests
 
+- `internal/releaseadapter/v071/search_empty_index_test.go`：空索引=空基线、有文档无范围字段必须报错。
 - `internal/httpapi/library_capture_test.go`：队列作业 id 必须放得进 `varchar(36)` 且形状固定。
 - `internal/releaseadapter/v071/search_tenant_filter_test.go`：接受未写租户、排除他租户、
   无租户字段时不造条件、整库过滤仍带知识库身份。
diff --git a/internal/releaseadapter/v071/library_search.go b/internal/releaseadapter/v071/library_search.go
index 6407ad3..161c31e 100644
--- a/internal/releaseadapter/v071/library_search.go
+++ b/internal/releaseadapter/v071/library_search.go
@@ -26,6 +26,22 @@ func (e *SearchExporter) ExportLibrary(ctx context.Context, identity SearchIdent
 		}
 		return SearchSnapshot{Documents: []SearchDocument{}, MappingSHA256: "", DocumentsSHA256: emptyDigest}, nil
 	}
+	if errors.Is(err, errScopeFieldsMissing) {
+		// 全新实例先用空映射建索引：没有范围字段、又确实 0 篇文档时就是空基线；
+		// 有文档却看不出归属必须报错（不能当成空库覆盖）。
+		empty, probeErr := e.emptyScopeIndex(ctx)
+		if probeErr != nil {
+			return SearchSnapshot{}, probeErr
+		}
+		if empty {
+			emptyDigest, digestErr := searchDocumentsDigest([]SearchDocument{})
+			if digestErr != nil {
+				return SearchSnapshot{}, digestErr
+			}
+			return SearchSnapshot{Documents: []SearchDocument{}, MappingSHA256: "", DocumentsSHA256: emptyDigest}, nil
+		}
+		return SearchSnapshot{}, err
+	}
 	if err != nil {
 		return SearchSnapshot{}, err
 	}
diff --git a/internal/releaseadapter/v071/search.go b/internal/releaseadapter/v071/search.go
index 1556b41..a9a908b 100644
--- a/internal/releaseadapter/v071/search.go
+++ b/internal/releaseadapter/v071/search.go
@@ -67,6 +67,23 @@ type searchFieldNames struct {
 // errIndexMissing 表示目标索引根本不存在（空生产基线）。
 var errIndexMissing = errors.New("Elasticsearch index missing")
 
+// errScopeFieldsMissing 表示索引存在但还没有发布范围字段：
+// 全新的 WeKnora 实例会先用空映射建好索引（`{}`），字段要等第一次写入才动态生成。
+// 这跟"索引被改坏了"必须分开：只有在索引里确实一篇文档都没有时才能当成空基线。
+var errScopeFieldsMissing = errors.New("Elasticsearch index mapping is missing release scope fields")
+
+// emptyScopeIndex 判断"没有范围字段"的索引是不是真的空。
+// 有文档却没有范围字段 = 无法判断这批文档属于谁，必须报错，不能当成 0。
+func (exporter *SearchExporter) emptyScopeIndex(ctx context.Context) (bool, error) {
+	var response struct {
+		Count int64 `json:"count"`
+	}
+	if err := exporter.requestJSON(ctx, http.MethodGet, "/"+exporter.index+"/_count", nil, &response); err != nil {
+		return false, err
+	}
+	return response.Count == 0, nil
+}
+
 type mappingInspection struct {
 	digest string
 	fields searchFieldNames
@@ -127,7 +144,7 @@ func (exporter *SearchExporter) inspectMapping(ctx context.Context) (mappingInsp
 		base:      resolve("knowledge_base_id"),
 	}
 	if fields.knowledge == "" || fields.base == "" {
-		return mappingInspection{}, errors.New("Elasticsearch index mapping is missing release scope fields")
+		return mappingInspection{}, errScopeFieldsMissing
 	}
 	return mappingInspection{digest: hex.EncodeToString(digest[:]), fields: fields}, nil
 }
diff --git a/internal/releaseadapter/v071/search_empty_index_test.go b/internal/releaseadapter/v071/search_empty_index_test.go
new file mode 100644
index 0000000..0ccb7e6
--- /dev/null
+++ b/internal/releaseadapter/v071/search_empty_index_test.go
@@ -0,0 +1,59 @@
+package v071
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+// 全新的 WeKnora 实例会先用空映射建索引（`{}`），字段等第一次写入才动态生成。
+// 这种索引不能被当成"索引被改坏了"：只有确实 0 篇文档时才是空基线；
+// 有文档却没有范围字段 = 不知道这批文档属于谁，必须报错。
+func TestEmptyScopeIndexCountsAsEmptyBaselineOnlyWhenTrulyEmpty(t *testing.T) {
+	for _, testCase := range []struct {
+		name     string
+		docCount int
+		wantErr  bool
+	}{
+		{"空索引当空基线", 0, false},
+		{"有文档但没有范围字段要报错", 7, true},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				switch r.URL.Path {
+				case "/chunks/_mapping":
+					_, _ = w.Write([]byte(`{"chunks":{"mappings":{}}}`))
+				case "/chunks/_count":
+					_ = json.NewEncoder(w).Encode(map[string]any{"count": testCase.docCount})
+				default:
+					http.NotFound(w, r)
+				}
+			}))
+			defer server.Close()
+			exporter, err := NewSearchExporter(SearchExporterConfig{BaseURL: server.URL, Index: "chunks", PageSize: 100})
+			if err != nil {
+				t.Fatalf("exporter: %v", err)
+			}
+			identity := SearchIdentity{TenantID: 10001, KnowledgeBaseID: "kb-1"}
+			count, countErr := exporter.Count(context.Background(), identity)
+			if testCase.wantErr {
+				if countErr == nil {
+					t.Fatalf("有文档却当成空基线：count=%d", count)
+				}
+			} else {
+				if countErr != nil || count != 0 {
+					t.Fatalf("空索引没有被当成空基线：count=%d err=%v", count, countErr)
+				}
+			}
+			_, exportErr := exporter.ExportLibrary(context.Background(), identity, 100)
+			if testCase.wantErr && exportErr == nil {
+				t.Fatal("导出把有文档的空映射索引当成空库")
+			}
+			if !testCase.wantErr && exportErr != nil {
+				t.Fatalf("空索引导出失败：%v", exportErr)
+			}
+		})
+	}
+}
diff --git a/internal/releaseadapter/v071/search_write.go b/internal/releaseadapter/v071/search_write.go
index 5b3a0e9..430e7dc 100644
--- a/internal/releaseadapter/v071/search_write.go
+++ b/internal/releaseadapter/v071/search_write.go
@@ -19,6 +19,17 @@ func (exporter *SearchExporter) Count(ctx context.Context, identity SearchIdenti
 		return 0, errors.New("invalid search identity")
 	}
 	inspection, err := exporter.inspectMapping(ctx)
+	if errors.Is(err, errScopeFieldsMissing) {
+		// 新建索引还没有范围字段：只有确实为空时才等于"这个范围 0 条"。
+		empty, probeErr := exporter.emptyScopeIndex(ctx)
+		if probeErr != nil {
+			return 0, probeErr
+		}
+		if empty {
+			return 0, nil
+		}
+		return 0, err
+	}
 	if err != nil {
 		return 0, err
 	}