AI agents for professionals in Peru

import random

class InvoiceServer:
    """Invented billing service: the first call is processed but its reply is lost."""
    def __init__(self):
        self.invoices, self.seen_keys, self.calls = [], {}, 0
    def create_invoice(self, client, amount, key=None):
        self.calls += 1
        if key in self.seen_keys:
            return self.seen_keys[key]            # same key: same invoice, no new one
        number = "F-%03d" % (len(self.invoices) + 1)
        self.invoices.append((number, client, amount))
        if key:
            self.seen_keys[key] = number
        if self.calls == 1:
            raise TimeoutError("no reply within 2 s")   # done, but the agent never hears
        return number

def naive(server):
    for attempt in range(1, 4):
        try:
            return server.create_invoice("Panaderia Sol", 120)
        except TimeoutError:
            pass                                   # retry at once, no key

def careful(server, max_attempts=4, base=1.0, cap=8.0, rng=random.Random(7)):
    key = "order-2026-118"                         # one key per real-world order
    for attempt in range(1, max_attempts + 1):
        try:
            return server.create_invoice("Panaderia Sol", 120, key=key)
        except TimeoutError:
            if attempt == max_attempts:
                break
            wait = rng.uniform(0, min(cap, base * 2 ** attempt))   # capped backoff, full jitter
            print("  attempt", attempt, "timed out; would wait", round(wait, 2), "s")  # printed, not slept
    return "HANDED TO A PERSON"

a = InvoiceServer(); print("naive  ->", naive(a), "| invoices:", [i[0] for i in a.invoices])
b = InvoiceServer(); print("careful->", careful(b), "| invoices:", [i[0] for i in b.invoices])

class DownServer(InvoiceServer):
    def create_invoice(self, client, amount, key=None):
        raise TimeoutError("service down")

print("down   ->", careful(DownServer()))

The service, client name, order and amount are invented by us. Waits are printed rather than slept so the lesson runs instantly; the random generator is seeded so the output is the same every time.

naive  -> F-002 | invoices: ['F-001', 'F-002']
  attempt 1 timed out; would wait 0.65 s
careful-> F-001 | invoices: ['F-001']
  attempt 1 timed out; would wait 0.3 s
  attempt 2 timed out; would wait 2.6 s
  attempt 3 timed out; would wait 0.58 s
down   -> HANDED TO A PERSON

Naive agent: two invoices. Careful agent: one invoice, after one wait. Against a service that is down, the careful agent tries four times, waits three times, and hands over.