Lesson packs live in separate files under lessons/. Add or edit lessons there. The engine should remain unchanged unless a lesson genuinely requires new capabilities.

window.CODE_QUEST.registerPack({
  id: "my-pack",
  type: "r",
  title: "My R Pack",
  description: "A custom lesson pack.",
  missions: [
    {
      mode: "reading",
      title: "Reading: Objects",
      readingTitle: "Why objects?",
      readingBody: () => "<p>Objects let you store values and reuse them later.</p>",
      xp: 40
    },
    {
      title: "Create x",
      task: () => "Create x containing 1, 2, 3.",
      hints: () => ["Use c()."],
      solution: () => "x <- c(1,2,3)",
      check: state => JSON.stringify(state.env.x) === "[1,2,3]",
      xp: 100
    }
  ]
});