Which open-source licenses let you sell a skill?

Permissive: MIT and Apache 2.0

You may use, change and sell work built on these projects. Keep the original copyright notice and license text with what you ship. Apache 2.0 also asks you to keep any NOTICE file and to say which files you changed.

Copyleft: GPL and AGPL

You may sell, but anything you distribute that includes the code must be released under the same license with its source. AGPL extends that to software people use over a network. In practice that rules them out for closed, paid skill packs.

Source-available and custom licenses

Some popular projects publish their code under their own terms. Read them before building on one. Some forbid redistribution, some require a paid license for companies, and some forbid derivative products.

What Lookbook does

• Paid skills build only on MIT, Apache 2.0 or CC0 projects.
• Every skill page names the project it builds on and its license.
• The original LICENSE and NOTICE files ship inside every download.