diff --git a/README.md b/README.md
index afe7e81..5e24fbd 100644
--- a/README.md
+++ b/README.md
@@ -67,7 +67,10 @@ response, state, task, error, and permission dimensions.
 
 Database migrations are ordered SQL files applied transactionally and recorded
 with SHA-256 checksums. Re-running `make db-migrate` is safe; changing an already
-applied migration is rejected instead of silently drifting the schema.
+applied migration is rejected instead of silently drifting the schema. Readiness
+stays unavailable until the latest packaged migration is present; task workers
+retry claims and recover automatically when migrations are applied after process
+startup.
 Seed profiles are deterministic and replace the previously seeded simulation
 state atomically. `small` creates one node, two QEMU guests, one LXC, two
 storages, an administrator, and completed task history. `medium` creates three
diff --git a/app/db/pool.py b/app/db/pool.py
index cef40b7..e0d04bf 100644
--- a/app/db/pool.py
+++ b/app/db/pool.py
@@ -8,6 +8,9 @@ import asyncpg  # type: ignore[import-untyped]
 from asyncpg import Pool
 
 from app.config import Settings
+from app.db.migrations import load_migrations
+
+LATEST_SCHEMA_VERSION = max(migration.version for migration in load_migrations())
 
 
 class Database(Protocol):
@@ -62,12 +65,18 @@ class AsyncpgDatabase:
             await pool.close()
 
     async def is_ready(self) -> bool:
-        """Check that PostgreSQL accepts a trivial query."""
+        """Check connectivity and that all packaged migrations are applied."""
 
         if self._pool is None:
             return False
         try:
-            return bool(await self._pool.fetchval("SELECT 1") == 1)
+            return bool(
+                await self._pool.fetchval(
+                    """SELECT COALESCE(max(version), 0) >= $1
+                    FROM schema_migrations""",
+                    LATEST_SCHEMA_VERSION,
+                )
+            )
         except asyncpg.PostgresError:
             return False
 
diff --git a/app/db/repositories/__init__.py b/app/db/repositories/__init__.py
new file mode 100644
index 0000000..3d9e325
--- /dev/null
+++ b/app/db/repositories/__init__.py
@@ -0,0 +1 @@
+"""Typed PostgreSQL repositories for simulation domain state."""
diff --git a/app/db/repositories/resources.py b/app/db/repositories/resources.py
new file mode 100644
index 0000000..a293695
--- /dev/null
+++ b/app/db/repositories/resources.py
@@ -0,0 +1,97 @@
+"""Typed resource persistence with explicit optimistic locking."""
+
+from __future__ import annotations
+
+import json
+import uuid
+from collections.abc import Mapping
+from dataclasses import dataclass
+from typing import Any, cast
+
+from asyncpg import Pool  # type: ignore[import-untyped]
+
+from app.db.primitives import ConflictError, transaction
+
+
+@dataclass(frozen=True, slots=True)
+class ResourceRecord:
+    id: uuid.UUID
+    cluster_id: uuid.UUID
+    node: str
+    kind: str
+    external_id: str
+    state: dict[str, Any]
+    metadata: dict[str, Any]
+    version: int
+
+
+def _json_object(value: object) -> dict[str, Any]:
+    if isinstance(value, str):
+        return cast(dict[str, Any], json.loads(value))
+    return dict(cast(Mapping[str, Any], value))
+
+
+def _record(row: Mapping[str, object]) -> ResourceRecord:
+    return ResourceRecord(
+        id=cast(uuid.UUID, row["id"]),
+        cluster_id=cast(uuid.UUID, row["cluster_id"]),
+        node=str(row["node"]),
+        kind=str(row["kind"]),
+        external_id=str(row["external_id"]),
+        state=_json_object(row["state"]),
+        metadata=_json_object(row["metadata"]),
+        version=int(cast(int, row["version"])),
+    )
+
+
+class ResourceRepository:
+    def __init__(self, pool: Pool) -> None:
+        self._pool = pool
+
+    async def list(
+        self, *, kind: str | None = None, node: str | None = None
+    ) -> list[ResourceRecord]:
+        rows = await self._pool.fetch(
+            """SELECT r.id, r.cluster_id, n.name AS node, r.kind, r.external_id,
+            r.state, r.metadata, r.version
+            FROM resources r JOIN nodes n ON n.id=r.node_id
+            WHERE ($1::text IS NULL OR r.kind=$1)
+              AND ($2::text IS NULL OR n.name=$2)
+            ORDER BY r.kind, r.external_id""",
+            kind,
+            node,
+        )
+        return [_record(row) for row in rows]
+
+    async def get(self, *, kind: str, external_id: str) -> ResourceRecord | None:
+        row = await self._pool.fetchrow(
+            """SELECT r.id, r.cluster_id, n.name AS node, r.kind, r.external_id,
+            r.state, r.metadata, r.version
+            FROM resources r JOIN nodes n ON n.id=r.node_id
+            WHERE r.kind=$1 AND r.external_id=$2""",
+            kind,
+            external_id,
+        )
+        return None if row is None else _record(row)
+
+    async def update_state(
+        self,
+        resource_id: uuid.UUID,
+        *,
+        expected_version: int,
+        state: Mapping[str, object],
+    ) -> ResourceRecord:
+        async with transaction(self._pool) as connection:
+            row = await connection.fetchrow(
+                """UPDATE resources SET state=$3::jsonb, version=version+1,
+                updated_at=now() WHERE id=$1 AND version=$2
+                RETURNING id, cluster_id,
+                    (SELECT name FROM nodes WHERE id=resources.node_id) AS node,
+                    kind, external_id, state, metadata, version""",
+                resource_id,
+                expected_version,
+                json.dumps(dict(state), sort_keys=True),
+            )
+            if row is None:
+                raise ConflictError("resource version conflict or resource missing")
+            return _record(row)
diff --git a/docker-compose.yml b/docker-compose.yml
index 8bc7a9d..1236883 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -46,7 +46,7 @@ services:
     image: nginx:1.28.0-alpine
     depends_on:
       simulator:
-        condition: service_healthy
+        condition: service_started
     ports:
       - "8007:8443"
     volumes:
diff --git a/docs/architecture.md b/docs/architecture.md
index 11da393..e2ee417 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -197,6 +197,12 @@ The first vertical release deliberately supports a small set of endpoints with
 complete stateful semantics. All other imported endpoints remain visibly
 unsupported until their handlers and compatibility tests exist.
 
+Database readiness includes the latest packaged migration version, not merely a
+successful connectivity query. Workers tolerate the documented container-first
+startup sequence by retrying failed claims until migration tables exist.
+Normalized resource writes use compare-and-swap version updates through a typed
+repository, so stale writers receive a domain conflict.
+
 ## Deployment model
 
 One Uvicorn process runs per container. Horizontal replicas coordinate through
diff --git a/docs/original-prompt-gap-plan.md b/docs/original-prompt-gap-plan.md
index ddb0c9b..5d5dd8d 100644
--- a/docs/original-prompt-gap-plan.md
+++ b/docs/original-prompt-gap-plan.md
@@ -29,7 +29,7 @@ live admin report renders the same evidence deterministically.
   LXC, disks, NICs, snapshots, backups, pools, users/groups/roles/ACLs/tokens and
   observed contracts. Preserve version, metadata, timestamps, and cluster-wide
   VMID uniqueness.
-- [ ] Make migration readiness explicit so workers cannot become permanently
+- [x] Make migration readiness explicit so workers cannot become permanently
   unhealthy before schema creation.
 - [x] Match the required `small` profile (one node, two QEMU, one LXC, two
   storages, administrator, completed tasks).
diff --git a/tests/integration/test_migrations.py b/tests/integration/test_migrations.py
index fdd215a..c63a166 100644
--- a/tests/integration/test_migrations.py
+++ b/tests/integration/test_migrations.py
@@ -6,7 +6,11 @@ import uuid
 import asyncpg  # type: ignore[import-untyped]
 import pytest
 
+from app.config import Settings
 from app.db.migrations import migrate
+from app.db.pool import AsyncpgDatabase
+from app.db.primitives import ConflictError
+from app.db.repositories.resources import ResourceRepository
 from app.simulation.seed import apply_seed, small_profile
 
 pytestmark = [
@@ -58,3 +62,34 @@ async def test_small_seed_is_idempotent() -> None:
         assert await connection.fetchval("SELECT count(*) FROM storage_contents") == 4
     finally:
         await connection.close()
+
+
+async def test_schema_readiness_and_optimistic_resource_repository() -> None:
+    url = os.environ["TEST_DATABASE_URL"]
+    connection = await asyncpg.connect(url)
+    database = AsyncpgDatabase(Settings(database_url=url))
+    try:
+        await migrate(connection)
+        await apply_seed(connection, small_profile())
+        await database.connect()
+        assert await database.is_ready()
+
+        repository = ResourceRepository(database.pool)
+        resource = await repository.get(kind="qemu", external_id="101")
+        assert resource is not None
+        updated = await repository.update_state(
+            resource.id,
+            expected_version=resource.version,
+            state={**resource.state, "status": "running"},
+        )
+        assert updated.version == resource.version + 1
+        assert updated.state["status"] == "running"
+        with pytest.raises(ConflictError):
+            await repository.update_state(
+                resource.id,
+                expected_version=resource.version,
+                state=resource.state,
+            )
+    finally:
+        await database.close()
+        await connection.close()