diff --git a/tests/authority-vector-primary.mjs b/tests/authority-vector-primary.mjs
index 46c70d6..a5bf085 100644
--- a/tests/authority-vector-primary.mjs
+++ b/tests/authority-vector-primary.mjs
@@ -33,6 +33,7 @@ const {
   isAuthorityVectorConfig,
   normalizeAuthorityVectorConfig,
   queryAuthorityTriviumNeighbors,
+  applyAuthorityBmeVectorManifest,
 } = await import("../vector/authority-vector-primary-adapter.js");
 const {
   findSimilarNodesByText: findSimilarNodesByTextFromIndex,
@@ -244,10 +245,36 @@ assert.equal(isAuthorityVectorConfig(config), true);
   const applyCall = triviumClient.calls.find(([name]) => name === "bmeVectorApply")?.[1];
   assert.equal(applyCall.items.length, 2);
   assert.equal(applyCall.links.length, 1);
+  assert.equal(applyCall.observedDim, 2);
+  assert.equal(String(applyCall.vectorSpaceId || "").startsWith("vs_"), true);
+  assert.equal(applyCall.items.every((item) => item.payload?.vectorSpaceId === applyCall.vectorSpaceId), true);
+  assert.equal(applyCall.items.every((item) => item.payload?.observedDim === 2), true);
   assert.equal(applyCall.items.every((item) => Array.isArray(item.vector) && item.vector.length > 0), true);
   assert.equal(result.timings.authorityDiagnostics.upsert.operation, "bmeVectorApply");
 }
 
+{
+  const { graph } = createAuthorityVectorGraph();
+  const triviumClient = createMockTriviumClient();
+  const entries = [
+    { nodeId: "node-a", text: "a", hash: "hash-a", index: 0 },
+    { nodeId: "node-b", text: "b", hash: "hash-b", index: 1 },
+  ];
+  graph.nodes[0].embedding = [1, 0, 0];
+  graph.nodes[1].embedding = [1, 0];
+  await assert.rejects(
+    () => applyAuthorityBmeVectorManifest(graph, { ...config, bmeVectorApplyReady: true }, entries, {
+      namespace: "st-bme::chat-authority-vector",
+      collectionId: "st-bme::chat-authority-vector",
+      chatId: "chat-authority-vector",
+      modelScope: "scope",
+      triviumClient,
+    }),
+    /single vector dimension/,
+  );
+  assert.equal(triviumClient.calls.some(([name]) => name === "bmeVectorApply"), false);
+}
+
 {
   const { graph } = createAuthorityVectorGraph();
   const triviumClient = createMockTriviumClient({ failBmeVectorApply: true });
diff --git a/vector/authority-vector-primary-adapter.js b/vector/authority-vector-primary-adapter.js
index a8c6bf2..a997e5e 100644
--- a/vector/authority-vector-primary-adapter.js
+++ b/vector/authority-vector-primary-adapter.js
@@ -5,6 +5,7 @@ import {
   AuthorityHttpError,
 } from "../runtime/authority-http-client.js";
 import { embedBatch } from "./embedding.js";
+import { deriveVectorSpace } from "./vector-space.js";
 
 export const AUTHORITY_VECTOR_MODE = "authority";
 export const AUTHORITY_VECTOR_SOURCE = "authority-trivium";
@@ -872,7 +873,7 @@ export async function upsertAuthorityTriviumEntries(graph, config = {}, entries
 }
 
 export async function applyAuthorityBmeVectorManifest(graph, config = {}, entries = [], options = {}) {
-  const items = buildAuthorityVectorItems(graph, entries, options);
+  let items = buildAuthorityVectorItems(graph, entries, options);
   const links = buildAuthorityLinkItems(graph, options).map((link) => ({
     src: buildNodeReference(link.fromId, options.namespace),
     dst: buildNodeReference(link.toId, options.namespace),
@@ -883,6 +884,29 @@ export async function applyAuthorityBmeVectorManifest(graph, config = {}, entrie
   if (missingVector) {
     throw new Error("BME vector apply requires vector for every item");
   }
+  const observedDim = items.reduce((dim, item) => {
+    const vectorDim = normalizeVector(item?.vector || item?.embedding).length;
+    if (!vectorDim) return dim;
+    if (!dim) return vectorDim;
+    return dim === vectorDim ? dim : -1;
+  }, 0);
+  if (observedDim < 0) {
+    const error = new Error("BME vector apply requires a single vector dimension per batch");
+    error.errorCategory = "vector-dimension-mismatch";
+    error.errorDomain = "embedding";
+    throw error;
+  }
+  const vectorSpace = observedDim > 0 ? deriveVectorSpace(config, observedDim) : null;
+  if (vectorSpace?.vectorSpaceId) {
+    items = items.map((item) => ({
+      ...item,
+      payload: {
+        ...(item.payload || {}),
+        vectorSpaceId: vectorSpace.vectorSpaceId,
+        observedDim: vectorSpace.observedDim,
+      },
+    }));
+  }
   throwIfAborted(options.signal);
   const client = createAuthorityTriviumClient(config, options);
   const startedAt = nowMs();
@@ -900,6 +924,8 @@ export async function applyAuthorityBmeVectorManifest(graph, config = {}, entrie
       graphRevision: Math.max(0, Math.floor(Number(options.revision) || 0)),
       modelScope: String(options.modelScope || ""),
       embeddingMode: config.embeddingMode || "client",
+      ...(vectorSpace?.vectorSpaceId ? { vectorSpaceId: vectorSpace.vectorSpaceId } : {}),
+      ...(observedDim > 0 ? { observedDim } : {}),
       items,
       links,
       idempotencyKey: [