diff --git a/agent_service/migrations/alembic.ini b/agent_service/migrations/alembic.ini
new file mode 100644
index 0000000..b9f1ad8
--- /dev/null
+++ b/agent_service/migrations/alembic.ini
@@ -0,0 +1,39 @@
+[alembic]
+script_location = migrations
+prepend_sys_path = .
+version_path_separator = os
+sqlalchemy.url = postgresql+asyncpg://%(POSTGRES_USER)s:%(POSTGRES_PASSWORD)s@%(POSTGRES_HOST)s:%(POSTGRES_PORT)s/%(POSTGRES_DB)s
+
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S
diff --git a/agent_service/migrations/env.py b/agent_service/migrations/env.py
new file mode 100644
index 0000000..0d5a030
--- /dev/null
+++ b/agent_service/migrations/env.py
@@ -0,0 +1,64 @@
+import os
+import asyncio
+from logging.config import fileConfig
+from sqlalchemy import pool
+from sqlalchemy.engine import Connection
+from sqlalchemy.ext.asyncio import async_engine_from_config
+from alembic import context
+
+config = context.config
+
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# Override sqlalchemy.url from environment variables
+def get_url():
+    return (
+        f"postgresql+asyncpg://"
+        f"{os.environ['POSTGRES_USER']}:{os.environ['POSTGRES_PASSWORD']}"
+        f"@{os.environ['POSTGRES_HOST']}:{os.environ.get('POSTGRES_PORT', '5432')}"
+        f"/{os.environ['POSTGRES_DB']}"
+    )
+
+config.set_main_option("sqlalchemy.url", get_url())
+
+target_metadata = None
+
+
+def run_migrations_offline() -> None:
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def do_run_migrations(connection: Connection) -> None:
+    context.configure(connection=connection, target_metadata=target_metadata)
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async def run_async_migrations() -> None:
+    connectable = async_engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+    async with connectable.connect() as connection:
+        await connection.run_sync(do_run_migrations)
+    await connectable.dispose()
+
+
+def run_migrations_online() -> None:
+    asyncio.run(run_async_migrations())
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()
diff --git a/agent_service/migrations/versions/001_initial_schema.py b/agent_service/migrations/versions/001_initial_schema.py
new file mode 100644
index 0000000..8f862ad
--- /dev/null
+++ b/agent_service/migrations/versions/001_initial_schema.py
@@ -0,0 +1,162 @@
+"""Initial schema — memory, directive, session, LLM config, rate limit tables
+
+Revision ID: 001
+Revises:
+Create Date: 2026-04-12
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+revision = '001'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # -----------------------------------------------------------------------
+    # Tier 1: Conversation memory per user
+    # Hard cap: 200 rows per user — enforced in application layer before insert
+    # -----------------------------------------------------------------------
+    op.execute("""
+        CREATE TABLE IF NOT EXISTS ab_conversation_memory (
+            id SERIAL PRIMARY KEY,
+            user_id INTEGER NOT NULL,
+            role VARCHAR(16) NOT NULL,
+            content TEXT NOT NULL,
+            directive_id VARCHAR(64),
+            is_summary BOOLEAN DEFAULT FALSE,
+            created_at TIMESTAMP DEFAULT NOW()
+        )
+    """)
+    op.execute("""
+        CREATE INDEX IF NOT EXISTS idx_conv_user
+        ON ab_conversation_memory(user_id, created_at DESC)
+    """)
+
+    # -----------------------------------------------------------------------
+    # Tier 2: Operational memory — 90-day TTL
+    # -----------------------------------------------------------------------
+    op.execute("""
+        CREATE TABLE IF NOT EXISTS ab_operational_memory (
+            id SERIAL PRIMARY KEY,
+            scope VARCHAR(64) NOT NULL,
+            summary TEXT NOT NULL,
+            raw_data JSONB,
+            source_directive_id VARCHAR(64),
+            expires_at TIMESTAMP,
+            created_at TIMESTAMP DEFAULT NOW()
+        )
+    """)
+    op.execute("""
+        CREATE INDEX IF NOT EXISTS idx_op_scope
+        ON ab_operational_memory(scope, created_at DESC)
+    """)
+
+    # -----------------------------------------------------------------------
+    # Tier 3: Long-term knowledge — permanent
+    # -----------------------------------------------------------------------
+    op.execute("""
+        CREATE TABLE IF NOT EXISTS ab_knowledge_store (
+            id SERIAL PRIMARY KEY,
+            entity_type VARCHAR(32) NOT NULL,
+            entity_key VARCHAR(128) NOT NULL,
+            facts JSONB NOT NULL,
+            updated_at TIMESTAMP DEFAULT NOW(),
+            UNIQUE(entity_type, entity_key)
+        )
+    """)
+
+    # -----------------------------------------------------------------------
+    # Directive execution graph
+    # -----------------------------------------------------------------------
+    op.execute("""
+        CREATE TABLE IF NOT EXISTS ab_directive_log (
+            id SERIAL PRIMARY KEY,
+            directive_id VARCHAR(64) UNIQUE NOT NULL,
+            user_id INTEGER NOT NULL,
+            channel_id INTEGER NOT NULL,
+            raw_message TEXT NOT NULL,
+            intent_summary TEXT,
+            agents_involved JSONB DEFAULT '[]',
+            peer_calls JSONB DEFAULT '[]',
+            actions_taken JSONB DEFAULT '[]',
+            escalations JSONB DEFAULT '[]',
+            final_response TEXT,
+            status VARCHAR(32) DEFAULT 'pending',
+            started_at TIMESTAMP DEFAULT NOW(),
+            completed_at TIMESTAMP,
+            error TEXT
+        )
+    """)
+    op.execute("""
+        CREATE INDEX IF NOT EXISTS idx_dir_user
+        ON ab_directive_log(user_id, started_at DESC)
+    """)
+    op.execute("""
+        CREATE INDEX IF NOT EXISTS idx_dir_status
+        ON ab_directive_log(status)
+    """)
+
+    # -----------------------------------------------------------------------
+    # Per-agent session state during execution
+    # -----------------------------------------------------------------------
+    op.execute("""
+        CREATE TABLE IF NOT EXISTS ab_agent_session (
+            id SERIAL PRIMARY KEY,
+            directive_id VARCHAR(64) NOT NULL,
+            agent_name VARCHAR(64) NOT NULL,
+            messages JSONB NOT NULL DEFAULT '[]',
+            status VARCHAR(32) DEFAULT 'running',
+            started_at TIMESTAMP DEFAULT NOW(),
+            completed_at TIMESTAMP
+        )
+    """)
+
+    # -----------------------------------------------------------------------
+    # LLM backend config — runtime per-agent model routing
+    # caller='__system__' stores the global privacy mode
+    # -----------------------------------------------------------------------
+    op.execute("""
+        CREATE TABLE IF NOT EXISTS ab_llm_config (
+            caller VARCHAR(64) PRIMARY KEY,
+            backend VARCHAR(16) NOT NULL,
+            set_by INTEGER,
+            set_at TIMESTAMP DEFAULT NOW(),
+            note TEXT
+        )
+    """)
+
+    # Seed default privacy mode = 'local'
+    op.execute("""
+        INSERT INTO ab_llm_config (caller, backend, note)
+        VALUES ('__system__', 'local', 'Default privacy mode — local Ollama only')
+        ON CONFLICT (caller) DO NOTHING
+    """)
+
+    # -----------------------------------------------------------------------
+    # Rate limiting
+    # -----------------------------------------------------------------------
+    op.execute("""
+        CREATE TABLE IF NOT EXISTS ab_rate_limit (
+            user_id INTEGER NOT NULL,
+            window_start TIMESTAMP NOT NULL,
+            request_count INTEGER DEFAULT 0,
+            PRIMARY KEY (user_id, window_start)
+        )
+    """)
+
+
+def downgrade() -> None:
+    op.execute("DROP TABLE IF EXISTS ab_rate_limit")
+    op.execute("DROP TABLE IF EXISTS ab_llm_config")
+    op.execute("DROP TABLE IF EXISTS ab_agent_session")
+    op.execute("DROP INDEX IF EXISTS idx_dir_status")
+    op.execute("DROP INDEX IF EXISTS idx_dir_user")
+    op.execute("DROP TABLE IF EXISTS ab_directive_log")
+    op.execute("DROP TABLE IF EXISTS ab_knowledge_store")
+    op.execute("DROP INDEX IF EXISTS idx_op_scope")
+    op.execute("DROP TABLE IF EXISTS ab_operational_memory")
+    op.execute("DROP INDEX IF EXISTS idx_conv_user")
+    op.execute("DROP TABLE IF EXISTS ab_conversation_memory")