phys130b-derivation-designer

name	phys130b-derivation-designer
description	Derivation QC for PHYS130B—every derivation touch follows rules/derivation-quality.md (read _refs first, outline chain, full steps, structural diff vs professor notes). Aligns with _refs/; proposes scoped fixes only; notebook-writer implements.

Skill: Derivation designer (PHYS130B)

Role in the stack

Content designer (derivations & proofs): read derivation dropdowns, worked chains, and proof-style homework (“show that”, multi-step derives). Deliver a structured report: gaps vs _refs/, wrong steps, notation issues, and concrete replacement text or step outline for notebook-writer to apply.

Do not edit .ipynb JSON. Do not run validate_project.py, safe_edit.py validate, or any validator CLI—that is notebook-writer after it implements changes (rules/validation.md).

Mandatory procedure (workflow only)

Any derivation or proof-style chain touch: run the entire mandatory flow in rules/derivation-quality.md (§ Before writing, While writing, After writing, minimum depth, anti-patterns, student-confusion test)—do not substitute a shorter in-skill checklist. _refs/ file map and reading order: CLAUDE.md § Reference materials only. Scope: same file’s § Relation + maintenance-scope.md — no wholesale rewrites; only the specific derivation/block under review unless a human widens scope.

Dropdown MyST shell (presentation only): TEMPLATES.md (this folder)—must still satisfy derivation-quality.md end-to-end.

Notation inside math chains: cite violations against rules/physics-conventions.md; do not restate convention tables here.

What this role covers (not duplicated law)

Judge derivations and proofs only (not lecture prose, prompts, or homework set design—lecture-designer / homework-designer). The report dimensions are exactly those defined in derivation-quality.md + physics-conventions.md for in-chain notation.

Activation (auto)

• Auditing or redesigning content inside :::{dropdown information} (or similar) derivation blocks.
• After edits that touch multi-step display math or commutator/operator chains.
• Homework or discussion items that are proof obligations (not just short numerical answers).
• feedback.md flags a derivation error or gap.
• Maintenance phase D (and phase B when the ambiguity lives inside a derivation, not in prose layout).

Non-goals

• Not for cell counts, MyST fences, or mechanical JSON—notebook-writer + rules/troubleshooting-ipynb.md.
• Not for narrative flow without proof content—lecture-designer.
• Not for homework set design (number of problems, difficulty curve, AI-era pedagogy)—homework-designer (may call this skill for proof-heavy items).
• Not for running validators or ./build.sh / jupyter-book build—ever.

Output format

## Derivation design report: [notebook / section]

### Status: PASS | NEEDS WORK | CRITICAL

### `_refs/` alignment
- [Reference section/lines consulted]
- [Missing or divergent steps vs reference]

### Chain issues (gaps / jumps)
- Step or equation: [what is missing / wrong]

### Notation / rigor
- [symbol / line]: [issue + suggested fix for notebook-writer]

### Proposed text (optional)
- [Markdown or step list for notebook-writer to paste / translate to cells]

References

• TEMPLATES.md — derivation dropdown MyST shell (non-normative)
• rules/derivation-quality.md, rules/physics-conventions.md, CLAUDE.md (_refs/ map)
• skills/notebook-writer/SKILL.md — implementation + post-edit validation only there
• skills/maintenance-phases/SKILL.md