Each plan includes a monthly AI allowance. When you reach it — a coverage read on a full script, a week of Agent Mode — there are three ways forward.
Wait
The allowance resets on the first of the month. Skills that would exceed it stop at the Run button and say when the reset is.
Add a credit pack
Settings → Plan & usage sells credit packs: a one-off, prepaid amount of AI use that sits on top of the allowance. Credits do not expire at the month end, the page shows the balance, and they are spent once you have turned on overage below.
Turn on overage
Credits and overage are two halves of one prepaid flow. Use credits when my plan's allowance runs out (Settings → Plan & usage → Overage) lets runs keep going past the allowance by drawing your credit balance down. It is off by default. There is no month-end bill and no separate cap to set: the credits you have bought are the ceiling. When the balance runs low, new runs pause until you add more — the same stop at the Run button as the allowance. Turn on Automatically buy more credits when I run low to have Inkwell buy another pack of the size you choose instead of pausing.
Or use your own key
With an Anthropic or OpenAI key of your own, AI use is billed by the provider to you and never touches the allowance. See Bring your own key.