Validate agent SQL before running

Agents hallucinate table names and mismatch placeholder counts. db.validate() parses and bind-checks SQL server-side without executing it, surfacing the same structured error detail a real query would return — for zero row reads. Wire it into the agent loop as a pre-flight gate.

import { PerSQL } from "@persql/sdk";

const persql = new PerSQL({ token: process.env.PERSQL_TOKEN! });
const db = persql.database("acme/orders");

async function planAndRun(sql: string, params: unknown[]) {
  const check = await db.validate(sql, params);
  if (!check.ok) {
    console.log("Validation failed:", check.error);
    console.log("Detail:", check.errorDetail);
    return check;
  }
  return db.query(sql, params);
}

// Catches unknown table before a query burns budget
await planAndRun("SELECT * FROM ordrs WHERE id = ?", [1]);

// Catches param mismatch
await planAndRun("SELECT * FROM orders WHERE id = ? AND status = ?", [1]);

Validation uses the same parser as execution, so false positives are impossible. Errors include the exact kind, table, column, and hint the agent needs to self-correct without retrying.

Next step

Self-heal agent SQL errors