Build your plugin in your own public GitHub repo, with a valid .claude-plugin/plugin.json at the root.
Open the plugin-submission issue (button on the right) and fill in your name, owner/repo, description, and category.
A maintainer reviews it and adds an entry to marketplace.json that points at your repo — your code never moves.
Once merged, it installs as /plugin install <name>@agora and shows up in the catalog here.