Use whenever the user wants to ingest a new course's materials (lecture notes, textbook chapters, HW problems, HW solutions) and build the course-specific knowledge base — patterns.md (recurring solution techniques), coverage.md (HW-to-section map with 🔥 exam tiers + ⚠weak flags), and summary.md (topic tree). Invoked by `/ingest` and `/analyze` slash commands. Designed to be domain-general across math and physics courses (calculus, linear algebra, real/complex analysis, classical mechanics, E&M, thermodynamics, quantum, etc.).
Use whenever the user uploads a hand-written or scanned answer PDF to be graded against a reference solution. Converts answer PDFs in `answers/*.pdf` to markdown in `answers/converted/*.md` using the pdf skill (OCR as needed), then performs strategy-based grading against `converted/solutions/*.md` or `quizzes/*_answers.md`. Invoked by `/grade`.
Use whenever the user works with PDF files — reading/extracting text from PDFs (lecture notes, textbook chapters, HW problems, HW solutions, hand-written answers), converting PDFs to markdown for downstream analysis, merging/splitting PDFs, or creating PDFs. For scanned or hand-written PDFs, OCR is required (pytesseract + pdf2image). Based on Anthropic's official PDF skill (github.com/anthropics/skills/tree/main/skills/pdf).
Use when the user wants exam-focused drilling from the course's analyzed material. Generates twin variants of known problems (`/twin`), runs strategy-level blind drills on known problems (`/blind`), creates integration problems chaining multiple patterns (`/chain`), surfaces pattern cards (`/pattern`), and shows coverage/exam-tier maps (`/hwmap`). Reads from `course-index/patterns.md`, `course-index/coverage.md`, and `converted/solutions/*.md`. Works for any math/physics course that has been ingested and analyzed.
Parse an Exam Radar (OPTIMETA Alt plugin) export and fold its lecture-emphasis exam-probability signal into the PAIDEIA course index — write course-index/radar.md, annotate course-index/coverage.md with a lecture-emphasis column and divergence flags, and seed a gold-zone weakmap. Invoked by /paideia:alt. The export form is fixed (exam-radar:v1 marker).
Use whenever a hand-written or scanned answer PDF needs transcription to markdown for /grade. Three tiers — Claude native vision (default, no extra install), local Qwen3-VL 8B via ollama (opt-in privacy mode), pytesseract fallback. The engine is selected via `OCR_ENGINE` in `.course-meta` (written by /paideia:init-course) and can be overridden per-call with `/paideia:grade --ocr=<engine>`.