diff --git a/README.md b/README.md
index 72fc13c..70e7191 100644
--- a/README.md
+++ b/README.md
@@ -104,6 +104,8 @@ DATABASE_URL=postgresql://postgres:postgres@postgres:5432/remote_coding_agent
 
 Database will be created automatically when you start with `docker compose --profile with-db`.
 
+If you previously started the old compose config, reset the local DB volume once with `docker compose --profile with-db down -v` before bringing it back up.
+
 </details>
 
 ---
diff --git a/docker-compose.yml b/docker-compose.yml
index 9598576..d5025bf 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -47,7 +47,8 @@ services:
       POSTGRES_USER: postgres
       POSTGRES_PASSWORD: postgres
     volumes:
-      - postgres_data:/var/lib/postgresql/data
+      # Postgres 18+ expects the volume at /var/lib/postgresql to manage its own versioned directories.
+      - postgres_data:/var/lib/postgresql
       - ./migrations:/docker-entrypoint-initdb.d
     ports:
       - "${POSTGRES_PORT:-5432}:5432"