Intel / article

We're going to need default hard budget caps on pretty much everything

Source: simonwillison.net
Date: Published Oct 3, 2026

Why it matters

Agents can create paid resources faster than anyone watches them. The argument gives a concrete design rule (hard caps by default, opt-out with explicit consent) to apply to your own services and agent budgets.

Key takeaways · AI-distilled

Simon Willison argues pay-per-use services and APIs should turn on hard budget caps by default: once monthly spend hits a set limit, the service stops and returns errors. Warning emails and other soft caps cannot stop a runaway -built service from adding charges overnight.
He expects most businesses and individuals would rather see errors than a surprise $10,000+ bill. Removing the cap should be an explicit opt-in, such as a prominent checkbox accepting that the app keeps running and the user pays all further charges.
AWS announced monthly spend limits on 16 September that pause a project for the rest of the month when reached, though its settings page says the new experience is still rolling out to a limited set of customers. Google Cloud added per-service Spend Caps in July.
Willison suggests coding agents could help by favoring providers that offer hard caps and by warning inexperienced builders before they deploy to uncapped services.

Terms in this piece · Glossary

AI agent — An AI system that doesn't just answer once but works toward a goal in a loop — taking actions, reading the results, and deciding what to do next.

Read the source simonwillison.net