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

Here's a product feature which the world is going to need a whole lot more of over the coming months and years: default hard budget caps . I'm talking about the feature of pay by usage services and APIs that lets you say "after $X/month, cut this thing off and return errors". These need to be hard limits. Soft caps,…

Simon Willison۱۱ مهر ۱۴۰۵ ۳ دقیقه مطالعهمتن اصلی

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

3rd October 2026

Here’s a product feature which the world is going to need a whole lot more of over the coming months and years: default hard budget caps. I’m talking about the feature of pay-by-usage services and APIs that lets you say “after $X/month, cut this thing off and return errors”. These need to be hard limits. Soft caps, “after $X/month, send me a warning email”, will not cut it.

Coding agents, and personal agents (coding agents wrapped in a less threatening UI), greatly reduce the friction of spinning up code that can do useful things. Sometimes those things cost money—calls to paid APIs, or hosted web applications, or systems that can bill for additional storage and compute.