[Phase 3.1] Achievement & Badge System

[robinson]

Goal

Implement a non-manipulative achievement and badge system that celebrates genuine
learning milestones.

Design Principles

• Badges reward learning behaviours (e.g. "Asked 10 deep questions"), NOT
  mere time spent.
• No dark patterns: no badge loss, no artificial scarcity, no FOMO prompts.
• Badges are private by default; sharing is opt-in.

Scope

• Backend (eule-core): POST /achievements/check endpoint; SQLite table
  achievements(id, user_id, badge_slug, earned_at).
• Frontend: Badge showcase screen; toast notification on earn; badge detail
  modal with explanation of why it was earned.
• Initial badge set: First Question, First Deep-Dive, Streak 3, Streak 7,
  10 Sessions, Subject Explorer (3 subjects), Night Owl, Early Bird.

Acceptance Criteria

• Earning a badge creates a record in SQLite and surfaces a toast.
• Badge showcase lists all earned badges with date and reason.
• No badge can be earned more than once (idempotent check logic).
• Badges are not displayed to parents on the dashboard without child consent.

References

• docs/UX_REDESIGN_STRATEGY.md — Part 5: Gamification System
• eule-core/src/storage/sqlite.rs (current schema)

Phase

Phase 3 — Gamification & Progress · Week 1–2