What problem does it solve? Generated apps need a real persistence layer, but wiring up an external database like Supabase adds setup friction and credentials management. This Skill gives every Doable project a built-in, isolated PostgreSQL-compatible (PGlite) database so app data is stored and queried without any external service. ## Core Features & Use Cases - Schema migrations at build time: Create tables with data.migrate using idempotent, ordered migration IDs, then verify structure with data.schema before writing app code. - Mandatory row-level security: Every table gets a created_by column, RLS enabled, and an owner policy so each user only sees their own rows, with support for multi-tenant workspace policies. - Runtime queries from app code: Generated React/TypeScript apps import the pre-linked @doable/data package and run parameterized SELECT/INSERT/UPDATE/DELETE statements with typed { ok, rows, error } results. - Use Case: A user asks for a task tracker app. The Skill creates a tasks table via data.migrate with RLS, verifies it with data.schema, then generates app code that inserts and lists tasks through db.query — no Supabase, no localStorage. ## Quick Start Ask the AI to build an app that saves user data, and it will create the database schema with data.migrate and wire the app to the built-in database automatically.