diff --git a/README.md b/README.md
index 09558ed..8c2a52e 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,9 @@ Un chatbot de WhatsApp para gestionar tareas en grupos, integrado con Evolution
   - RQ_MAX_ATTEMPTS: reintentos máximos; por defecto 6.
   - RQ_BASE_BACKOFF_MS: backoff base en ms; por defecto 5000.
   - RQ_MAX_BACKOFF_MS: backoff máximo en ms; por defecto 3600000.
+- Opcionales — migraciones
+  - MIGRATOR_CHECKSUM_STRICT: si "false" desactiva validación estricta de checksum de migraciones; por defecto "true".
+  - MIGRATIONS_LOG_PATH: ruta del fichero de log de migraciones; por defecto data/migrations.log.
 - Entorno
   - NODE_ENV: production | development | test.
 
diff --git a/STATUS.md b/STATUS.md
index a3306d5..39d576d 100644
--- a/STATUS.md
+++ b/STATUS.md
@@ -12,7 +12,7 @@ Estado general: listo para piloto con la junta directiva; 170 tests pasando. Rie
   - Inicialización con PRAGMA FK y timestamps de alta precisión.
   - Esquema: users, tasks, task_assignments, user_preferences, response_queue (con metadata).
   - Modo journal WAL activado (busy_timeout y autocheckpoint configurados) para mejorar concurrencia y rendimiento.
-  - Migrador up-only con tabla schema_migrations; backup automático con VACUUM INTO; baseline si existe esquema previo.
+  - Migrador up-only con tabla schema_migrations; FK siempre ON al abrir; backup automático con VACUUM INTO; sin baseline por defecto; validación de checksum; log persistente en data/migrations.log; resumen de estado al arrancar.
 - Cola de respuestas
   - Persistente con workers en background, reintentos con backoff exponencial + jitter, recuperación de items processing tras reinicios, y limpieza/retención.
   - 2xx=sent, 4xx=failed definitivo, 5xx/red=reintento; evita enviar al propio bot.
@@ -78,6 +78,7 @@ Estado general: listo para piloto con la junta directiva; 170 tests pasando. Rie
 
 ## Notas de despliegue/operación
 - SQLite en modo WAL; backups consistentes con VACUUM INTO previo; tener en cuenta archivos -wal y -shm.
+- Log persistente de migraciones en data/migrations.log (una línea por evento, formato JSONL); revisar en despliegues.
 - Persistencia en data/; mapear a volumen y monitorizar tamaño; ejecutar VACUUM periódicamente si procede.
 - Rotación de logs vía orquestador; considerar niveles/etiquetas para búsquedas.
 
diff --git a/src/db.ts b/src/db.ts
index 4081380..2c25bb8 100644
--- a/src/db.ts
+++ b/src/db.ts
@@ -2,6 +2,7 @@ import { Database } from 'bun:sqlite';
 import { normalizeWhatsAppId } from './utils/whatsapp';
 import { mkdirSync } from 'fs';
 import { join } from 'path';
+import { Migrator } from './db/migrator';
 
 function applyDefaultPragmas(instance: Database): void {
   try {
@@ -10,6 +11,8 @@ function applyDefaultPragmas(instance: Database): void {
     instance.query(`PRAGMA journal_mode = WAL`).get();
     instance.exec(`PRAGMA synchronous = NORMAL;`);
     instance.exec(`PRAGMA wal_autocheckpoint = 1000;`);
+    // Asegurar claves foráneas siempre activas
+    instance.exec(`PRAGMA foreign_keys = ON;`);
   } catch (e) {
     console.warn('[db] No se pudieron aplicar PRAGMAs (WAL, busy_timeout...):', e);
   }
@@ -31,172 +34,17 @@ export function getDb(filename: string = 'tasks.db'): Database {
 // Default export for the main application database
 export const db = getDb();
 
-// Initialize function now accepts a database instance
+ // Initialize function now accepts a database instance
 export function initializeDatabase(instance: Database) {
-  // Aplicar PRAGMAs por defecto (WAL, busy_timeout, etc.)
+  // Aplicar PRAGMAs por defecto (WAL, busy_timeout, FK, etc.)
   applyDefaultPragmas(instance);
 
-  // Enable foreign key constraints
-  instance.exec(`PRAGMA foreign_keys = ON;`);
-
-  // Create users table first as others depend on it
-  // Use TEXT for timestamps to store higher precision ISO8601 format easily
-  instance.exec(`
-    CREATE TABLE IF NOT EXISTS users (
-      id TEXT PRIMARY KEY, -- WhatsApp user ID (normalized)
-      first_seen TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
-      last_seen TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now'))
-    );
-  `);
-
-  // Create groups table
-  instance.exec(`
-    CREATE TABLE IF NOT EXISTS groups (
-      id TEXT PRIMARY KEY, -- Group ID (normalized)
-      community_id TEXT NOT NULL,
-      name TEXT,
-      last_verified TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
-      active BOOLEAN DEFAULT TRUE
-    );
-  `);
-
-  // Create group_members table
-  instance.exec(`
-    CREATE TABLE IF NOT EXISTS group_members (
-      group_id TEXT NOT NULL,
-      user_id TEXT NOT NULL,
-      is_admin BOOLEAN NOT NULL DEFAULT 0,
-      is_active BOOLEAN NOT NULL DEFAULT 1,
-      first_seen_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
-      last_seen_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
-      last_role_change_at TEXT NULL,
-      PRIMARY KEY (group_id, user_id),
-      FOREIGN KEY (group_id) REFERENCES groups(id) ON DELETE CASCADE,
-      FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
-    );
-  `);
-
-  // Indexes for membership lookups
-  instance.exec(`
-    CREATE INDEX IF NOT EXISTS idx_group_members_group_active
-    ON group_members (group_id, is_active);
-  `);
-  instance.exec(`
-    CREATE INDEX IF NOT EXISTS idx_group_members_user_active
-    ON group_members (user_id, is_active);
-  `);
-
-  // Create tasks table
-  instance.exec(`
-    CREATE TABLE IF NOT EXISTS tasks (
-      id INTEGER PRIMARY KEY AUTOINCREMENT,
-      description TEXT NOT NULL,
-      created_at TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
-      due_date TEXT NULL, -- Store dates as ISO8601 strings or YYYY-MM-DD
-      completed BOOLEAN DEFAULT FALSE,
-      completed_at TEXT NULL,
-      group_id TEXT NULL, -- Normalized group ID
-      created_by TEXT NOT NULL, -- Normalized user ID
-      completed_by TEXT NULL, -- Normalized user ID who completed the task
-      FOREIGN KEY (created_by) REFERENCES users(id) ON DELETE CASCADE,
-      FOREIGN KEY (completed_by) REFERENCES users(id) ON DELETE SET NULL,
-      FOREIGN KEY (group_id) REFERENCES groups(id) ON DELETE SET NULL -- Optional: Link task to group
-    );
-  `);
-    
-  // Create task_assignments table
-  instance.exec(`
-    CREATE TABLE IF NOT EXISTS task_assignments (
-      task_id INTEGER NOT NULL,
-      user_id TEXT NOT NULL, -- Normalized user ID
-      assigned_by TEXT NOT NULL, -- Normalized user ID
-      assigned_at TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
-      PRIMARY KEY (task_id, user_id),
-      FOREIGN KEY (task_id) REFERENCES tasks(id) ON DELETE CASCADE,
-      FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
-      FOREIGN KEY (assigned_by) REFERENCES users(id) ON DELETE CASCADE
-    );
-  `);
-
-  // Create response_queue table (persistent outbox for replies)
-  instance.exec(`
-    CREATE TABLE IF NOT EXISTS response_queue (
-      id INTEGER PRIMARY KEY AUTOINCREMENT,
-      recipient TEXT NOT NULL,
-      message TEXT NOT NULL,
-      status TEXT NOT NULL DEFAULT 'queued' CHECK (status IN ('queued','processing','sent','failed')),
-      attempts INTEGER NOT NULL DEFAULT 0,
-      last_error TEXT NULL,
-      metadata TEXT NULL,
-      created_at TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
-      updated_at TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now'))
-    );
-  `);
-
-  // Index to fetch pending items efficiently
-  instance.exec(`
-    CREATE INDEX IF NOT EXISTS idx_response_queue_status_created_at
-    ON response_queue (status, created_at);
-  `);
-
-  // Migration: ensure 'metadata' column exists on response_queue for message options (e.g., mentions)
+  // Ejecutar migraciones up-only (sin baseline por defecto). Evitar backup duplicado aquí.
   try {
-    const cols = instance.query(`PRAGMA table_info('response_queue')`).all() as any[];
-    const hasMetadata = Array.isArray(cols) && cols.some((c: any) => c.name === 'metadata');
-    if (!hasMetadata) {
-      instance.exec(`ALTER TABLE response_queue ADD COLUMN metadata TEXT NULL;`);
-    }
-  } catch (e) {
-    console.warn('[initializeDatabase] Skipped adding response_queue.metadata column:', e);
-  }
-
-  // Migration: ensure 'completed_by' column exists on tasks (to record who completed)
-  try {
-    const cols = instance.query(`PRAGMA table_info('tasks')`).all() as any[];
-    const hasCompletedBy = Array.isArray(cols) && cols.some((c: any) => c.name === 'completed_by');
-    if (!hasCompletedBy) {
-      instance.exec(`ALTER TABLE tasks ADD COLUMN completed_by TEXT NULL;`);
-    }
-  } catch (e) {
-    console.warn('[initializeDatabase] Skipped adding tasks.completed_by column:', e);
-  }
-
-  // Migration: ensure reliability columns exist on response_queue (next_attempt_at, lease_until, last_status_code)
-  try {
-    const cols = instance.query(`PRAGMA table_info('response_queue')`).all() as any[];
-    const hasNextAttempt = Array.isArray(cols) && cols.some((c: any) => c.name === 'next_attempt_at');
-    if (!hasNextAttempt) {
-      instance.exec(`ALTER TABLE response_queue ADD COLUMN next_attempt_at TEXT NULL;`);
-    }
-    const hasLeaseUntil = Array.isArray(cols) && cols.some((c: any) => c.name === 'lease_until');
-    if (!hasLeaseUntil) {
-      instance.exec(`ALTER TABLE response_queue ADD COLUMN lease_until TEXT NULL;`);
-    }
-    const hasLastStatus = Array.isArray(cols) && cols.some((c: any) => c.name === 'last_status_code');
-    if (!hasLastStatus) {
-      instance.exec(`ALTER TABLE response_queue ADD COLUMN last_status_code INTEGER NULL;`);
-    }
-  } catch (e) {
-    console.warn('[initializeDatabase] Skipped ensuring response_queue reliability columns:', e);
-  }
-
-  // Ensure supporting indexes exist
-  try {
-    instance.exec(`
-      CREATE INDEX IF NOT EXISTS idx_response_queue_status_next_attempt
-      ON response_queue (status, next_attempt_at);
-    `);
-  } catch (e) {
-    console.warn('[initializeDatabase] Skipped creating idx_response_queue_status_next_attempt:', e);
-  }
-
-  try {
-    instance.exec(`
-      CREATE INDEX IF NOT EXISTS idx_response_queue_status_lease_until
-      ON response_queue (status, lease_until);
-    `);
+    Migrator.migrateToLatest(instance, { withBackup: false, allowBaseline: false });
   } catch (e) {
-    console.warn('[initializeDatabase] Skipped creating idx_response_queue_status_lease_until:', e);
+    console.error('[initializeDatabase] Error al aplicar migraciones:', e);
+    throw e;
   }
 }
 
diff --git a/src/db/migrator.ts b/src/db/migrator.ts
index 97821eb..fab6b21 100644
--- a/src/db/migrator.ts
+++ b/src/db/migrator.ts
@@ -1,5 +1,5 @@
 import type { Database } from 'bun:sqlite';
-import { mkdirSync } from 'fs';
+import { mkdirSync, appendFileSync } from 'fs';
 import { join } from 'path';
 import { migrations, type Migration } from './migrations';
 
@@ -7,6 +7,16 @@ function nowIso(): string {
   return new Date().toISOString().replace('T', ' ').replace('Z', '');
 }
 
+function logEvent(level: 'info' | 'error', event: string, data: any = {}) {
+  try {
+    mkdirSync('data', { recursive: true });
+  } catch {}
+  try {
+    const line = JSON.stringify({ ts: nowIso(), level, event, ...data });
+    appendFileSync(join('data', 'migrations.log'), line + '\n');
+  } catch {}
+}
+
 function ensureMigrationsTable(db: Database) {
   db.exec(`
     CREATE TABLE IF NOT EXISTS schema_migrations (
@@ -44,7 +54,7 @@ function insertMigrationRow(db: Database, mig: Migration) {
   ).run(mig.version, mig.name, mig.checksum, nowIso());
 }
 
-async function backupDatabaseIfNeeded(db: Database): Promise<string | null> {
+function backupDatabaseIfNeeded(db: Database): string | null {
   if (process.env.NODE_ENV === 'test') return null;
   try {
     mkdirSync('data', { recursive: true });
@@ -66,14 +76,33 @@ export const Migrator = {
   ensureMigrationsTable,
   getAppliedVersions,
 
-  async migrateToLatest(db: Database, options?: { withBackup?: boolean; allowBaseline?: boolean }) {
+  migrateToLatest(db: Database, options?: { withBackup?: boolean; allowBaseline?: boolean }) {
     const withBackup = options?.withBackup !== false;
-    const allowBaseline = options?.allowBaseline !== false;
+    const allowBaseline = options?.allowBaseline === true;
 
     ensureMigrationsTable(db);
     const applied = getAppliedVersions(db);
     const pending = migrations.filter(m => !applied.has(m.version)).sort((a, b) => a.version - b.version);
 
+    // Validación de checksum (estricta por defecto, configurable)
+    const strict = (process.env.MIGRATOR_CHECKSUM_STRICT ?? 'true').toLowerCase() !== 'false';
+    for (const [version, info] of applied) {
+      const codeMig = migrations.find(m => m.version === version);
+      if (codeMig && codeMig.checksum !== info.checksum) {
+        const msg = `❌ Checksum mismatch en migración v${version}: aplicado=${info.checksum}, código=${codeMig.checksum}`;
+        console.error(msg);
+        try { logEvent('error', 'checksum_mismatch', { version, applied_checksum: info.checksum, code_checksum: codeMig.checksum }); } catch {}
+        if (strict) throw new Error(msg);
+      }
+    }
+
+    // Resumen inicial
+    const jmRow = db.query(`PRAGMA journal_mode`).get() as any;
+    const journalMode = jmRow ? (jmRow.journal_mode || jmRow.value || jmRow.mode || 'unknown') : 'unknown';
+    const currentVersion = applied.size ? Math.max(...Array.from(applied.keys())) : 0;
+    console.log(`ℹ️ Migrador — journal_mode=${journalMode}, versión_actual=${currentVersion}, pendientes=${pending.length}`);
+    try { logEvent('info', 'startup_summary', { journal_mode: journalMode, current_version: currentVersion, pending: pending.length }); } catch {}
+
     if (applied.size === 0 && allowBaseline && detectExistingSchema(db)) {
       // Baseline a v1 si ya existe el esquema pero no hay registro
       const v1 = migrations.find(m => m.version === 1)!;
@@ -81,22 +110,27 @@ export const Migrator = {
         insertMigrationRow(db, v1);
       })();
       console.log('ℹ️ Baseline aplicado: schema_migrations marcada en v1 (sin ejecutar up)');
+      try { logEvent('info', 'baseline_applied', { version: 1 }); } catch {}
       // Recalcular pendientes
       pending.splice(0, pending.length, ...migrations.filter(m => m.version > 1));
     }
 
     if (pending.length === 0) {
       console.log('ℹ️ No hay migraciones pendientes');
+      try { logEvent('info', 'no_pending', {}); } catch {}
       return;
     }
 
     if (withBackup) {
-      await backupDatabaseIfNeeded(db);
+      const backupPath = backupDatabaseIfNeeded(db);
+      try { logEvent('info', 'backup', { path: backupPath }); } catch {}
     }
 
     for (const mig of pending) {
       console.log(`➡️ Aplicando migración v${mig.version} - ${mig.name}`);
       try {
+        try { logEvent('info', 'apply_start', { version: mig.version, name: mig.name, checksum: mig.checksum }); } catch {}
+        const t0 = Date.now();
         db.transaction(() => {
           // Ejecutar up
           const res = mig.up(db);
@@ -106,9 +140,12 @@ export const Migrator = {
           // Registrar
           insertMigrationRow(db, mig);
         })();
-        console.log(`✅ Migración v${mig.version} aplicada`);
+        const ms = Date.now() - t0;
+        console.log(`✅ Migración v${mig.version} aplicada (${ms} ms)`);
+        try { logEvent('info', 'apply_success', { version: mig.version, name: mig.name, checksum: mig.checksum, duration_ms: ms }); } catch {}
       } catch (e) {
         console.error(`❌ Error aplicando migración v${mig.version}:`, e);
+        try { logEvent('error', 'apply_error', { version: mig.version, name: mig.name, checksum: mig.checksum, error: String(e) }); } catch {}
         throw e;
       }
     }