Fader Transfer Gate

Problem

Open-ended AI tutors can over-help. A learner may fish for the answer through hints and still fail when asked to apply the concept independently. Teachers need evidence of transfer after support is removed, not another transcript that proves only persistence in a chat.

Solution

Fader is a state-gated education protocol for one authored concept: confidence-interval interpretation. It records a baseline, allows at most two conceptual supports, runs an assisted retry, locks the independent transfer item from hints and chat, and emits a deterministic PASS or NEEDS_REVIEW receipt with a bounded next intervention.

Product features

Validated lesson manifest with a finite misconception rubric, support policy, and authored transfer variants.
Coach me flow: BASELINE -> bounded supports -> ASSISTED_RETRY -> TRANSFER_LOCKED -> RECEIPT_READY.
Explain concept and Show example practice modes that cannot emit transfer receipts.
Hard support cap of two and API rejection of support after transfer lock.
Separate independent explanation required before scoring.
Authored answer key remains the sole authority for PASS and NEEDS_REVIEW.
GPT-5.6 structured misconception classification and hint wording within a fixed rubric, with visible deterministic fallback.
Durable protected sessions, teacher queue, receipt download, canonical verification, optional HMAC authentication, and pitch deck.

GPT-5.6 and Codex

GPT-5.6 can classify a learner explanation and draft a bounded conceptual hint with evidence spans and no answer-letter leakage. It cannot reveal the answer, unlock transfer, score the item, or write the intervention. Codex built the validated lesson manifest, protocol state machine, support adapter, protected session and teacher flows, UI, CLI, receipts, verification, and tests.

Judge proof

Run npm ci, npm test, and npm start with the demo teacher token and receipt signing secret. Choose Coach me, submit the intentional wrong baseline, use at most two supports, complete the assisted retry, answer the locked transfer item with an independent explanation, and inspect the signed receipt and next intervention.