PromptTools is an open-source toolkit designed to provide developers with a free and open suite of tools for testing and experimenting. It offers a range of interfaces and methods that allow developers to use familiar code and notebook interfaces to evaluate prompts. By running experiments in a notebook and assessing the output, you can gain a better understanding of prompt effectiveness. You can also convert assessment results into unit tests and integrate them into your CI/CD workflows. A core philosophy of PromptTools is to enable developers to execute code locally rather than sending it to servers. This means all code runs on your local machine, which is particularly important for projects concerning data security and privacy.