Before you start · Plugin Builder

The builder is part of Premium. Planning, building and editing with AI need an active YourBot subscription on your account. The builder is an account feature, so it does not matter which server the subscription is assigned to, or whether it is assigned at all. Everything else in the developer portal stays free: the classic form, the CLI, manual upload, GitHub auto-deploy and publishing.
AI credits pay for the work. Each plan, build and AI edit is paid from the AI credit wallet on your account, the same wallet that pays for Start Your Server designs. What it costs explains how.
Running a plugin on a server needs a custom bot. Marketplace plugins, including the ones you build, run through a server's custom bot, which comes with a subscription. Until then you can test a plugin with the Dev Bot for 24 hours at a time.
Saving a plugin needs the Developer Agreement. If you have not accepted the current Developer Agreement, saving a draft as a plugin asks you to first, as every other way of creating a plugin does. Your draft is kept while you do.