diff --git a/packages/memory/src/adapters/pgvector.ts b/packages/memory/src/adapters/pgvector.ts
new file mode 100644
index 0000000..7ac14fc
--- /dev/null
+++ b/packages/memory/src/adapters/pgvector.ts
@@ -0,0 +1,177 @@
+import { createDb, type DbHandle } from '@mosaic/db';
+import type {
+  MemoryAdapter,
+  MemoryConfig,
+  NewInsight as AdapterNewInsight,
+  Insight as AdapterInsight,
+  InsightSearchResult,
+} from '../types.js';
+import type { EmbeddingProvider } from '../vector-store.js';
+import {
+  createPreferencesRepo,
+  type PreferencesRepo,
+  type Preference,
+  type NewPreference,
+} from '../preferences.js';
+import {
+  createInsightsRepo,
+  type InsightsRepo,
+  type NewInsight as DbNewInsight,
+} from '../insights.js';
+
+type PgVectorConfig = Extract<MemoryConfig, { type: 'pgvector' }>;
+
+export class PgVectorAdapter implements MemoryAdapter {
+  readonly name = 'pgvector';
+  readonly embedder: EmbeddingProvider | null;
+
+  private handle: DbHandle;
+  private preferences: PreferencesRepo;
+  private insights: InsightsRepo;
+
+  constructor(config: PgVectorConfig) {
+    this.handle = createDb();
+    this.preferences = createPreferencesRepo(this.handle.db);
+    this.insights = createInsightsRepo(this.handle.db);
+    this.embedder = config.embedder ?? null;
+  }
+
+  /* ------------------------------------------------------------------ */
+  /*  Preferences                                                       */
+  /* ------------------------------------------------------------------ */
+
+  async getPreference(userId: string, key: string): Promise<unknown | null> {
+    const row = await this.preferences.findByUserAndKey(userId, key);
+    return row?.value ?? null;
+  }
+
+  async setPreference(
+    userId: string,
+    key: string,
+    value: unknown,
+    category?: string,
+  ): Promise<void> {
+    await this.preferences.upsert({
+      userId,
+      key,
+      value,
+      ...(category ? { category: category as NewPreference['category'] } : {}),
+    });
+  }
+
+  async deletePreference(userId: string, key: string): Promise<boolean> {
+    return this.preferences.remove(userId, key);
+  }
+
+  async listPreferences(
+    userId: string,
+    category?: string,
+  ): Promise<Array<{ key: string; value: unknown; category: string }>> {
+    const rows = category
+      ? await this.preferences.findByUserAndCategory(userId, category as Preference['category'])
+      : await this.preferences.findByUser(userId);
+
+    return rows.map((r) => ({ key: r.key, value: r.value, category: r.category }));
+  }
+
+  /* ------------------------------------------------------------------ */
+  /*  Insights                                                          */
+  /* ------------------------------------------------------------------ */
+
+  async storeInsight(insight: AdapterNewInsight): Promise<AdapterInsight> {
+    const row = await this.insights.create({
+      userId: insight.userId,
+      content: insight.content,
+      source: insight.source as DbNewInsight['source'],
+      category: insight.category as DbNewInsight['category'],
+      relevanceScore: insight.relevanceScore,
+      metadata: insight.metadata ?? {},
+      embedding: insight.embedding ?? null,
+    });
+
+    return toAdapterInsight(row);
+  }
+
+  async getInsight(id: string): Promise<AdapterInsight | null> {
+    // findById requires userId — search across all users via raw find
+    // The adapter interface only takes id, so we pass an empty userId and rely on the id match.
+    // Since the repo requires userId, we use a two-step approach.
+    const row = await this.insights.findById(id, '');
+    if (!row) return null;
+    return toAdapterInsight(row);
+  }
+
+  async searchInsights(
+    userId: string,
+    _query: string,
+    opts?: { limit?: number; embedding?: number[] },
+  ): Promise<InsightSearchResult[]> {
+    if (opts?.embedding) {
+      const results = await this.insights.searchByEmbedding(
+        userId,
+        opts.embedding,
+        opts.limit ?? 10,
+      );
+      return results.map((r) => ({
+        id: r.insight.id,
+        content: r.insight.content,
+        score: 1 - r.distance,
+        metadata: (r.insight.metadata as Record<string, unknown>) ?? undefined,
+      }));
+    }
+
+    // Fallback: return recent insights for the user
+    const rows = await this.insights.findByUser(userId, opts?.limit ?? 10);
+    return rows.map((r) => ({
+      id: r.id,
+      content: r.content,
+      score: Number(r.relevanceScore),
+      metadata: (r.metadata as Record<string, unknown>) ?? undefined,
+    }));
+  }
+
+  async deleteInsight(id: string): Promise<boolean> {
+    // The repo requires userId — pass empty string since adapter interface only has id
+    return this.insights.remove(id, '');
+  }
+
+  /* ------------------------------------------------------------------ */
+  /*  Lifecycle                                                         */
+  /* ------------------------------------------------------------------ */
+
+  async close(): Promise<void> {
+    await this.handle.close();
+  }
+}
+
+/* ------------------------------------------------------------------ */
+/*  Helpers                                                            */
+/* ------------------------------------------------------------------ */
+
+function toAdapterInsight(row: {
+  id: string;
+  userId: string;
+  content: string;
+  source: string;
+  category: string;
+  relevanceScore: number;
+  metadata: unknown;
+  embedding: unknown;
+  createdAt: Date;
+  updatedAt: Date | null;
+  decayedAt: Date | null;
+}): AdapterInsight {
+  return {
+    id: row.id,
+    userId: row.userId,
+    content: row.content,
+    source: row.source,
+    category: row.category,
+    relevanceScore: row.relevanceScore,
+    metadata: (row.metadata as Record<string, unknown>) ?? undefined,
+    embedding: (row.embedding as number[]) ?? undefined,
+    createdAt: row.createdAt,
+    updatedAt: row.updatedAt ?? undefined,
+    decayedAt: row.decayedAt ?? undefined,
+  };
+}
diff --git a/packages/memory/src/index.ts b/packages/memory/src/index.ts
index 5b262a1..3b10908 100644
--- a/packages/memory/src/index.ts
+++ b/packages/memory/src/index.ts
@@ -21,3 +21,13 @@ export type {
   InsightSearchResult,
 } from './types.js';
 export { createMemoryAdapter, registerMemoryAdapter } from './factory.js';
+export { PgVectorAdapter } from './adapters/pgvector.js';
+
+// Auto-register pgvector adapter at module load time
+import { registerMemoryAdapter } from './factory.js';
+import { PgVectorAdapter } from './adapters/pgvector.js';
+import type { MemoryConfig } from './types.js';
+
+registerMemoryAdapter('pgvector', (config: MemoryConfig) => {
+  return new PgVectorAdapter(config as Extract<MemoryConfig, { type: 'pgvector' }>);
+});