A language-learning game for primary-school children, about four to ten, with a teacher platform behind it. Teachers author short spoken quests with an AI co-author and approve every step; children play them in a world of clay monsters and answer by speaking, in English or Austrian German. The AI never reaches the child: every line was written or approved by a teacher, and every answer is judged by code against the answers the teacher accepted.
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05One sentence: “I want to teach shapes to 2nd year primary class.” Reading level and subject are checked before anything is sent.
Pictures or not? What should the children be able to do by the end? Nothing reaches a child until the teacher approves it.
Outcome, keywords from the school’s catalogue, one activity, the cast. A new word, “triangle”, is coined and queued for review rather than slipped in.
Every beat has a setup, a spoken prompt and three recorded outcomes: correct, try again, reveal. Checks read the text for safety, reading level, structure and mood arc. Pass or flag, never a score.
The mission’s closing film starts as a story the teacher signs off: where it happens, the fact children take home, the word they hear. Only then is it scripted, pictured and rendered.
In the browser, in a world of clay monsters. The child answers by speaking, judged against the teacher’s accepted answers, deterministically. The platform never stores the audio.
Four agents turn a quest into a narrated film. Failure, retry and refund are per slot, not per film, and timeouts are sized from the measured worst case, not guessed.
Stack → Flue · Hono · Gemini · fal.ai · Resemble · ffmpeg · Cloud Run
Each character’s sheet, camera grammar and style register compiled into agent prompts at build. Trait schemas are hash-locked to the reference plates by tests, and the vision judge was calibrated until it caught every planted defect without failing a good frame.
Stack → Canon as a package · derived schemas · calibrated vision judge
Agent workflows and skills co-author quests in English and German. Invented words are dropped by code. The model writes emotion tags; a deterministic compiler writes the SSML.
Stack → Gemini · Ideogram v4 · Resemble · promptfoo · OpenTelemetry
Row-level security forced in the database, not just checked in the app. A credit ledger where reserve, commit and refund share one transaction and one row lock, so a failed render is refunded exactly once. Covered by unit, integration and browser tests.
Stack → Fastify · Prisma · Postgres · Next.js 16 · React 19 · Stripe · Turborepo
Contact — open application, always
Same person, two lenses. Both are A4 drawing sheets in the Blueprint theme.
One design system, five themes. The CV wears the first, the letters the second. The other three are here — try them, the whole site follows.