Here's a tool to install and manage these limit keys. Even has a GUI.

$ uvx capit serve

https://github.com/day50-dev/limit-model-spending

* Free to use

* Everything is stored local.

* Anthropic skills are included for easily extending it to additional tools or providers.

Please ask for features or file bugs. Thanks!

Btw, I'm terrible at marketing even when I'm giving stuff away.