Your AI writes KernScript. You save money.

(tool weather
  (desc "Current weather for a city")
  (in  {city: str}) (out {temp: num, desc: str})
  (let d (fetch "https://api.example.com/weather" {q: city}))
  {temp: d.temp, desc: d.text})

(agent helper
  (model "claude-sonnet-4-6")
  (tools [weather]) (permission [:net]))

(let r (ask helper "Weather in Madrid?"))
(print r.text)

import http from 'node:http';
import Database from 'better-sqlite3';
const db = new Database(process.env.DATABASE_URL || ':memory:');
db.exec(`CREATE TABLE IF NOT EXISTS authors (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, email TEXT UNIQUE, created TEXT);
CREATE TABLE IF NOT EXISTS posts (id INTEGER PRIMARY KEY AUTOINCREMENT, title TEXT, body TEXT, author REAL, published INTEGER, created TEXT);
CREATE TABLE IF NOT EXISTS comments (id INTEGER PRIMARY KEY AUTOINCREMENT, post REAL, text TEXT, created TEXT);`);
const TOKEN = process.env.AUTH_TOKEN;
const json = (res, code, obj) => { res.writeHead(code, { 'content-type': 'application/json' }); res.end(obj === undefined ? '' : JSON.stringify(obj)); };
const readBody = async (req) => { const c = []; for await (const x of req) c.push(x); return c.length ? JSON.parse(Buffer.concat(c).toString()) : {}; };
const authed = (req) => { const m = (req.headers['authorization'] || '').match(/^Bearer\s+(.+)$/i); return !!m && m[1] === TOKEN; };
const row = (t, id) => db.prepare('SELECT * FROM ' + t + ' WHERE id = ?').get(id);
const now = () => new Date().toISOString();
const server = http.createServer(async (req, res) => {
  const p = new URL(req.url, 'http://x').pathname;
  const method = req.method;
  if ((method === 'POST' || method === 'PUT' || method === 'DELETE') && !authed(req)) return json(res, 401, { error: 'unauthorized' });
  const mComments = p.match(/^\/posts\/(\d+)\/comments$/);
  const mPost = p.match(/^\/posts\/(\d+)$/);
  if (method === 'POST' && p === '/authors') {
    const b = await readBody(req);
    if (typeof b.name !== 'string' || typeof b.email !== 'string') return json(res, 400, { error: 'invalid' });
    const i = db.prepare('INSERT INTO authors (name, email, created) VALUES (?, ?, ?)').run(b.name, b.email, now());
    return json(res, 200, row('authors', i.lastInsertRowid));
  }
  if (method === 'GET' && p === '/authors') return json(res, 200, db.prepare('SELECT * FROM authors').all());
  if (method === 'POST' && p === '/posts') {
    const b = await readBody(req);
    if (typeof b.title !== 'string' || typeof b.body !== 'string' || typeof b.author !== 'number' || typeof b.published !== 'boolean') return json(res, 400, { error: 'invalid' });
    const i = db.prepare('INSERT INTO posts (title, body, author, published, created) VALUES (?, ?, ?, ?, ?)').run(b.title, b.body, b.author, b.published ? 1 : 0, now());
    return json(res, 200, row('posts', i.lastInsertRowid));
  }
  if (method === 'GET' && p === '/posts') return json(res, 200, db.prepare('SELECT * FROM posts ORDER BY created').all());
  if (method === 'GET' && mPost) { const r = row('posts', mPost[1]); return r ? json(res, 200, r) : json(res, 404, { error: 'post not found' }); }
  if (method === 'PUT' && mPost) {
    const b = await readBody(req);
    if (typeof b.title !== 'string' || typeof b.body !== 'string') return json(res, 400, { error: 'invalid' });
    db.prepare('UPDATE posts SET title = ?, body = ? WHERE id = ?').run(b.title, b.body, mPost[1]);
    return json(res, 200, row('posts', mPost[1]));
  }
  if (method === 'DELETE' && mPost) { db.prepare('DELETE FROM posts WHERE id = ?').run(mPost[1]); return json(res, 204, undefined); }
  if (method === 'POST' && mComments) {
    const b = await readBody(req);
    if (typeof b.text !== 'string') return json(res, 400, { error: 'invalid' });
    const i = db.prepare('INSERT INTO comments (post, text, created) VALUES (?, ?, ?)').run(Number(mComments[1]), b.text, now());
    return json(res, 200, row('comments', i.lastInsertRowid));
  }
  if (method === 'GET' && mComments) return json(res, 200, db.prepare('SELECT * FROM comments WHERE post = ?').all(Number(mComments[1])));
  if (method === 'GET' && p === '/stats') return json(res, 200, { authors: db.prepare('SELECT COUNT(*) n FROM authors').get().n, posts: db.prepare('SELECT COUNT(*) n FROM posts').get().n, comments: db.prepare('SELECT COUNT(*) n FROM comments').get().n });
  if (method === 'GET' && p === '/health') return json(res, 200, { status: 'up' });
  json(res, 404, { error: 'not found' });
});
server.listen(Number(process.env.PORT), () => console.log(`serving on http://localhost:${server.address().port}`));