explaining-derivationslisted

# Explaining Derivations ## Overview **An expansion that cannot be completed is evidence against the derivation.** That is the thesis, and it is what separates this skill from pedagogy. Making a proof explicit is useful in itself — but the moment a step resists being made explicit, you have learned something about the proof rather than about the reader. A step nobody can justify leaves this skill as a gap-ledger row with a severity, and that ledger feeds back into the review as findings. So the deliverable is two things at once: a standalone LaTeX document per theorem, readable by an undergraduate engineer or an ML graduate student without formal maths training, **and** a ledger of every step that could not be written down. **Core principle: never manufacture a justification.** The register that reads best is also the one that most invites a plausible-sounding reason for a step nobody checked. Every guard below exists for that. ## Run it ```sh python3 ~/.claude/skills/explaining-derivations/assets/run-explain.py main.tex \ --out derivations/ --level grad-ml --plan-only ``` Run it by absolute path from the paper directory. Stdlib only — no install, no venv. `latexmk` is used if present, never installed; absent, the `.tex` is still written and the run exits `2`. - `--plan-only` **first, always.** A dozen theorems is a dozen subagents. It prints the plan and dispatches nothing. - `--level undergrad | grad-ml | expert-shorthand` — see `reference/registers.md` - `--