Rubric-based AI assisted grading
How to implement AI assisted grading in a learning platform: a draft grade per criterion, evidence quoted from the student, and the teacher's signature.
The version almost every platform builds first is a general model with a system prompt saying "you are a tutor for this course". It works in the demo and fails in class, because the student asks about the notation that instructor uses, the example in unit three, the rubric criterion. None of that is in the model.
The version that actually works starts with the content: transcribe the video, split the material into passages with their references, and build retrieval before conversation. The tutor is the last layer, not the first — and the cheaper of the two.
Short answer
A useful AI tutor isn't a general chat with the course's name on it: it's a system that retrieves passages from your own material, answers citing the module and the timestamp, says "that isn't in this unit" when it isn't, and when facing a graded assignment guides to the step before without solving it.
Timestamped video transcription, splitting material into passages, and metadata for course, unit and learning objective. This is half the project's work.
Only the courses they're enrolled in and the units they've already unlocked. A tutor that answers with unit seven's material wrecks the course's pedagogical sequence.
Every claim comes with the passage supporting it and a link to the video timestamp or the page. No passage, no claim: the tutor says it isn't in the material.
The tutor recognizes when a question is literally the graded prompt and switches mode: it explains the concept, offers an analogous exercise, and withholds the answer. That boundary is tested against the course's real assignment texts.
How to implement AI assisted grading in a learning platform: a draft grade per criterion, evidence quoted from the student, and the teacher's signature.
How to generate assessment items with AI from your own material: aligned to the learning objective, with plausible distractors and review before publishing.
How to implement semantic search in a learning platform: over transcribed video and your own material, citing the timestamp and respecting the student's scope.