wiki/decisions/ADR-008-merge-lesson-design-and-activity.md
ADR-008: Merge Lesson Design and Activity Derivation
Date: 2026-06-04 Status: Accepted
Context
The per-book factory had Module 3 for lesson design and Module 3b for experiment derivation. Review showed that the household activity is not a downstream add-on; it is part of the pedagogical design of the book.
Decision
Merge M3 and M3b into one Lesson Design + Activity module. The module produces both LessonBlueprint and ActivitySheet.
Rationale
CurioQuest is a story + activity product. The activity should be designed with the big idea, clue chain, misconception correction, learning check, and reward so the experiment reenacts the story's climax rather than feeling bolted on. This removes a separate gate while keeping the safety review inside M3.
Alternatives Considered
| Option | Why rejected |
|---|---|
| Keep M3b as a separate module | Adds an extra review pass and separates the activity from the lesson intent. |
| Put activity generation later in page planning | Too late; the activity must shape pedagogy and story, not merely fill pages. |
Consequences
The product spec is now v1.2. Former M3b is deprecated as a separate operation but ActivitySheet remains a first-class artifact for contracts, rendering, safety checks, and caching.