diff --git a/src/metamemory/index.ts b/src/metamemory/index.ts
index 13a4cea..d71c193 100644
--- a/src/metamemory/index.ts
+++ b/src/metamemory/index.ts
@@ -15,7 +15,7 @@ import { InMemoryVectorSearch } from './utils/vector-search.js';
 import type { ResponseInput, ResponseInputItem, Agent } from '@just-every/ensemble';
 
 // Re-export types for backward compatibility
-export type { MetamemoryState } from '../metamemory-old/types';
+export type { MetamemoryState } from './types';
 
 export interface MetaMemoryOptions {
   config?: Partial<MetaMemoryConfig>;
@@ -30,6 +30,7 @@ export class Metamemory {
   private tagger: MessageTagger;
   private compactor: ThreadCompactor;
   private contextAssembler: ContextAssembler;
+  private vectorSearch: InMemoryVectorSearch;
   private config: MetaMemoryConfig;
   private isProcessing: boolean = false;
   private messageQueue: ResponseInputItem[] = [];
@@ -56,10 +57,10 @@ export class Metamemory {
     this.tagger = new MessageTagger(taggerLLM, this.config);
     
     const summarizer = options.summarizer || new LLMSummarizer(options.agent);
-    const vectorSearch = options.vectorSearch as InMemoryVectorSearch || new InMemoryVectorSearch();
-    
-    this.compactor = new ThreadCompactor(this.threadManager, this.config, summarizer, vectorSearch);
-    this.contextAssembler = new ContextAssembler(this.threadManager, vectorSearch);
+    this.vectorSearch = options.vectorSearch as InMemoryVectorSearch || new InMemoryVectorSearch();
+
+    this.compactor = new ThreadCompactor(this.threadManager, this.config, summarizer, this.vectorSearch);
+    this.contextAssembler = new ContextAssembler(this.threadManager, this.vectorSearch);
   }
   
   /**
@@ -200,7 +201,8 @@ export class Metamemory {
       metamemory: new Map(), // Empty for now
       threads: threadMap,
       lastProcessedIndex: this.lastProcessedIndex,
-      lastProcessedTime: Date.now()
+      lastProcessedTime: Date.now(),
+      vectorEmbeddings: this.vectorSearch.exportEmbeddings()
     };
   }
   
@@ -229,6 +231,17 @@ export class Metamemory {
     
     this.threadManager.importThreads(threads);
     this.lastProcessedIndex = state.lastProcessedIndex;
+
+    this.vectorSearch.clear();
+    if (state.vectorEmbeddings) {
+      this.vectorSearch.loadEmbeddings(state.vectorEmbeddings);
+    } else {
+      for (const thread of Object.values(threads)) {
+        if (thread.state === 'archived') {
+          void this.vectorSearch.addThread(thread);
+        }
+      }
+    }
   }
   
   /**
@@ -266,6 +279,7 @@ export function createMetamemoryState(): MetamemoryStateType {
     metamemory: new Map(),
     threads: new Map(),
     lastProcessedIndex: 0,
-    lastProcessedTime: Date.now()
+    lastProcessedTime: Date.now(),
+    vectorEmbeddings: {}
   };
 }
\ No newline at end of file
diff --git a/src/metamemory/types/index.ts b/src/metamemory/types/index.ts
index 7c4a605..0e68b0b 100644
--- a/src/metamemory/types/index.ts
+++ b/src/metamemory/types/index.ts
@@ -1,7 +1,18 @@
 export type TopicState = 'core' | 'active' | 'idle' | 'archived' | 'ephemeral';
 
 // Add the missing type for backwards compatibility
-export type { MetamemoryState } from '../../metamemory-old/types.js';
+import type { MetamemoryState as LegacyMetamemoryState } from '../../metamemory-old/types.js';
+
+export interface VectorEmbeddings {
+  [topicName: string]: {
+    summary: string;
+    embedding: number[];
+  };
+}
+
+export interface MetamemoryState extends LegacyMetamemoryState {
+  vectorEmbeddings?: VectorEmbeddings;
+}
 
 export interface Message {
   id: string;
diff --git a/src/metamemory/utils/vector-search.ts b/src/metamemory/utils/vector-search.ts
index 608b43b..28b8ef8 100644
--- a/src/metamemory/utils/vector-search.ts
+++ b/src/metamemory/utils/vector-search.ts
@@ -104,13 +104,38 @@ export class InMemoryVectorSearch implements VectorSearchInterface {
   clear(): void {
     this.embeddings.clear();
   }
-  
+
   /**
    * Get the number of indexed threads
    */
   size(): number {
     return this.embeddings.size;
   }
+
+  /**
+   * Export embeddings for persistence
+   */
+  exportEmbeddings(): Record<string, { summary: string; embedding: number[] }> {
+    const data: Record<string, { summary: string; embedding: number[] }> = {};
+    for (const [topicName, value] of this.embeddings) {
+      data[topicName] = { summary: value.summary, embedding: value.embedding };
+    }
+    return data;
+  }
+
+  /**
+   * Load embeddings from persisted state
+   */
+  loadEmbeddings(data: Record<string, { summary: string; embedding: number[] }>): void {
+    this.embeddings.clear();
+    for (const [topicName, value] of Object.entries(data)) {
+      this.embeddings.set(topicName, {
+        topicName,
+        summary: value.summary,
+        embedding: value.embedding,
+      });
+    }
+  }
 }
 
 /**
diff --git a/test/metamemory-new.test.ts b/test/metamemory-new.test.ts
index eb38453..82a4e64 100644
--- a/test/metamemory-new.test.ts
+++ b/test/metamemory-new.test.ts
@@ -311,5 +311,27 @@ describe('MetaMemory System', () => {
       const newState = metamemory.getState();
       expect(newState.threads.size).toBe(1);
     });
+
+    it('should preserve vector search data after restoring state', async () => {
+      // Create an archived thread and index it
+      const manager: any = (metamemory as any).threadManager;
+      const search: InMemoryVectorSearch = (metamemory as any).vectorSearch;
+
+      const thread = manager.createThread('archived_topic', 'archived');
+      manager.updateThreadSummary('archived_topic', 'Discussion about caching data');
+      await search.addThread(thread);
+
+      const saved = metamemory.getState();
+
+      const restored = new Metamemory({
+        agent: mockAgent,
+        taggerLLM: new MockTaggerLLM(),
+        summarizer: new MockSummarizer(),
+      });
+
+      restored.restoreState(saved);
+      const results = await (restored as any).vectorSearch.search('caching', 1);
+      expect(results[0].topicName).toBe('archived_topic');
+    });
   });
 });
\ No newline at end of file