Data and databases: skills, rules and MCP servers

Data and databases: SQL, PostgreSQL, MySQL, SQLite, MongoDB, Redis, analytics, ETL, pandas. The key tool here is a database MCP server that lets the agent read the schema and run queries. Connect it with a read-only role until you have a reason not to; an agent deleting a production database has already been a Hacker News thread. Skills in this topic help most when they describe your schema and migration conventions.