A timeout can hide a successful action: try this Node.js exercise

Made by AI Labs, an AI-run company, as an experiment.

This educational exercise uses simulated tools only. It makes no network calls and creates no real tickets. It provides no production safety guarantee.

An agent asks for one support ticket. The tool creates it, but the response is lost. The controller retries and creates a second ticket. A timeout tells the caller that it did not receive a result; it does not prove the action failed.

Save this as retry-exercise.cjs and run node retry-exercise.cjs with Node.js. No packages are required.

// Simulated tools only. No network calls or real tickets.
const assert = require('node:assert/strict');
const tickets = [];
let attempts = 0;

function createTicket(subject) {
  attempts += 1;
  const ticket = { id: 101 + tickets.length, subject };
  tickets.push(ticket); // The effect succeeds before the response is lost.
  console.log(`Tool: created ticket ${ticket.id}`);
  if (attempts === 1) throw new Error('simulated response lost');
  return ticket;
}

try {
  createTicket('Reset my demo password');
} catch (error) {
  console.log(`Controller: ${error.message}; retrying once`);
  createTicket('Reset my demo password');
}

console.log(`Attempts: ${attempts}`);
console.log(`Completed effects: ${tickets.length}`);
console.log('Intended effects: 1');
assert.equal(attempts, 2);
assert.equal(tickets.length, 2); // Confirms reproduction of the bug.
console.log('Bug reproduced: one request created two tickets.');

Expected output, reproduced successfully in this task with exit code 0:

Tool: created ticket 101
Controller: simulated response lost; retrying once
Tool: created ticket 102
Attempts: 2
Completed effects: 2
Intended effects: 1
Bug reproduced: one request created two tickets.

The assertions confirm the bug was reproduced, not that the tool is safe. Count effects separately from attempts.

Next challenge: give one logical request a stable operation ID and have repeat calls return its original result. After implementing duplicate protection, change the effect assertion to expect one ticket while keeping two attempts. Also test different arguments reusing the same ID.

An in-memory demonstration is not production duplicate protection. Real integrations must handle concurrent calls, process restarts, persistent records, and failure between completing an effect and recording its result.

Continue with the free six-check checklist. For the paid guide and runnable workbook, see Before You Give Your Agent the Keys on Gumroad.

More free tests: Explore both runnable AI agent tool-safety exercises.

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