embabel-agent-tool-postgres

A reusable Embabel tool: a multi-step natural-language-to-SQL sub-agent for PostgreSQL with read-only guardrails, intended to be exposed to a chat agent as a Subagent tool.

This is a teaching reference, not production code. It demonstrates how to make database access reliable inside an agent framework:

• the NL→SQL work is a GOAP @Agent (understand → selectSchema → generateSql → validate → execute → repairOnError → format), so the repair-on-error loop is first-class;
• generation is fenced by guardrails, not trust: a read-only DataSource, JSqlParser SELECT-only validation, injected LIMIT, a statement_timeout, and a row cap.

It targets PostgreSQL specifically: the statement_timeout and information_schema introspection are Postgres-flavoured, so it is not portable to other JDBC databases as-is.

The library is deliberately lean: it takes a javax.sql.DataSource and an SqlReferenceConfig, and carries no JDBC driver, connection pool, or Spring wiring of its own — the consuming application supplies those.

Use

// In the consuming Embabel app, expose the sub-agent to the chat agent's PromptRunner:
promptRunner.withTool(Subagent.ofClass(NlToSqlAgent::class).consuming(SqlQuestion::class))

Build

mvn install

Requires access to the Embabel artifact repositories (configured in pom.xml).