diff --git a/retrieval/shared-ranking.js b/retrieval/shared-ranking.js
index 31014f1..994623e 100644
--- a/retrieval/shared-ranking.js
+++ b/retrieval/shared-ranking.js
@@ -435,6 +435,7 @@ export async function vectorPreFilter(
       topK,
       activeNodes,
       signal,
+      { readOnly: true },
     );
   } catch (error) {
     if (isAbortError(error)) {
diff --git a/tests/shared-ranking.mjs b/tests/shared-ranking.mjs
index 64582f3..288f43c 100644
--- a/tests/shared-ranking.mjs
+++ b/tests/shared-ranking.mjs
@@ -52,6 +52,7 @@ const { addEdge, addNode, createEdge, createEmptyGraph, createNode } = await imp
   "../graph/graph.js"
 );
 const { rankNodesForTaskContext } = await import("../retrieval/shared-ranking.js");
+const { deriveVectorSpace } = await import("../vector/vector-space.js");
 
 function setTestOverrides(overrides = {}) {
   globalThis.__stBmeTestOverrides = overrides;
@@ -110,6 +111,22 @@ addEdge(
   }),
 );
 
+const config = {
+  mode: "direct",
+  source: "direct",
+  apiUrl: "https://example.com/v1",
+  apiKey: "",
+  model: "test-embedding",
+};
+const currentVectorSpace = deriveVectorSpace(config, 3);
+graph.vectorIndexState.currentVectorSpace = currentVectorSpace;
+graph.vectorIndexState.manifest = {
+  status: "clean",
+  vectorSpaceId: currentVectorSpace.vectorSpaceId,
+  observedDim: currentVectorSpace.observedDim,
+  model: currentVectorSpace.model,
+};
+
 const graphBefore = JSON.stringify(graph);
 const restore = setTestOverrides({
   embedding: {
@@ -127,13 +144,6 @@ const restore = setTestOverrides({
 });
 
 try {
-  const config = {
-    mode: "direct",
-    source: "direct",
-    apiUrl: "https://example.com/v1",
-    apiKey: "",
-    model: "test-embedding",
-  };
   const first = await rankNodesForTaskContext({
     graph,
     userMessage: "[user]: 中文告白后的关系进展",
diff --git a/vector/vector-index.js b/vector/vector-index.js
index 11e2484..e26b6bb 100644
--- a/vector/vector-index.js
+++ b/vector/vector-index.js
@@ -1427,9 +1427,11 @@ export async function findSimilarNodesByText(
   topK = 10,
   candidates = null,
   signal = undefined,
+  options = {},
 ) {
   if (!text || !graph || !config) return [];
   throwIfAborted(signal);
+  const readOnly = options?.readOnly === true;
 
   const candidateNodes = Array.isArray(candidates)
     ? candidates
@@ -1441,6 +1443,7 @@ export async function findSimilarNodesByText(
       ? "direct"
       : "backend";
   const recordSearchTimings = (patch = {}) => {
+    if (readOnly) return;
     const state = graph?.vectorIndexState;
     if (!state || typeof state !== "object" || Array.isArray(state)) return;
     state.lastSearchTimings = {
@@ -1480,7 +1483,7 @@ export async function findSimilarNodesByText(
         reason: "vector-space-mismatch",
         resultCount: 0,
       });
-      if (state) {
+      if (!readOnly && state) {
         state.dirty = true;
         state.dirtyReason = "vector-space-mismatch";
         state.lastWarning = "向量空间不匹配，已切换到非向量召回并等待重建";
@@ -1508,11 +1511,13 @@ export async function findSimilarNodesByText(
         queryEmbedMs: roundMs(queryEmbedMs),
         resultCount: 0,
       });
-      state.dirty = true;
-      state.dirtyReason = "query-dimension-mismatch";
-      state.lastWarning = `查询向量维度 ${queryVec.length} 与索引维度 ${currentDim} 不一致，已切换到非向量召回`;
-      if (state.manifest) {
-        state.manifest = { ...state.manifest, status: "stale", lastError: "query-dimension-mismatch" };
+      if (!readOnly) {
+        state.dirty = true;
+        state.dirtyReason = "query-dimension-mismatch";
+        state.lastWarning = `查询向量维度 ${queryVec.length} 与索引维度 ${currentDim} 不一致，已切换到非向量召回`;
+        if (state.manifest) {
+          state.manifest = { ...state.manifest, status: "stale", lastError: "query-dimension-mismatch" };
+        }
       }
       return [];
     }
@@ -1564,9 +1569,11 @@ export async function findSimilarNodesByText(
           reason: "authority-vector-space-mismatch",
           resultCount: 0,
         });
-        state.dirty = true;
-        state.dirtyReason = "authority-vector-space-mismatch";
-        state.lastWarning = "Authority 向量空间不匹配，已切换到非向量召回并等待重建";
+        if (!readOnly) {
+          state.dirty = true;
+          state.dirtyReason = "authority-vector-space-mismatch";
+          state.lastWarning = "Authority 向量空间不匹配，已切换到非向量召回并等待重建";
+        }
         return [];
       }
     }
@@ -1618,13 +1625,15 @@ export async function findSimilarNodesByText(
       }
       const message = error?.message || String(error) || "Authority Trivium 查询失败";
       const errorPatch = getAuthorityDiagnosticsErrorPatch(error);
-      markAuthorityVectorStateDirty(
-        graph,
-        config,
-        "authority-trivium-query-failed",
-        `Authority Trivium 查询失败（${message}），已标记待重建`,
-        errorPatch,
-      );
+      if (!readOnly) {
+        markAuthorityVectorStateDirty(
+          graph,
+          config,
+          "authority-trivium-query-failed",
+          `Authority Trivium 查询失败（${message}），已标记待重建`,
+          errorPatch,
+        );
+      }
       recordSearchTimings({
         success: false,
         reason: "authority-trivium-query-failed",