The 50-page PRD HTML totals ~520KB; loading it all costs Claude ~222K
tokens just for context. This adds a token-efficient sibling layer:

- scripts/extract-spec.js → npm run spec:extract / spec:check
  Walks docs/prd/newfunction/*.html and produces stripped MD into _spec/.
  Strategy varies per page (full-extract for SDD/process/data,
  shell-strip for agents to keep long system prompts intact).
  Result: 327.9KB MD (~84K tokens) — 38% of full load, saves ~138K tokens
  for every Agent invocation that reads the spec.

- scripts/git-hooks/pre-commit + scripts/install-hooks.sh
  Pre-commit guard: when any docs/prd/newfunction/*.html changes, the
  hook checks the corresponding _spec/*.md is up to date; fails commit
  if stale, telling user to `npm run spec:extract`. Auto-installed via
  package.json `prepare` script on `npm install`.

- docs/prd/newfunction/_spec/ (51 .md files + CONVENTIONS.md)
  Machine-readable mirror of HTML. Used by:
  - Coder/Architect/Tester agents when reading spec at runtime
  - External Claude Code sessions doing reproducibility
  - CI checks (npm run spec:check)
  NOT hand-edited; regenerated from HTML by extract-spec.js.

- CLAUDE.md: 1-line note directing future agents to read _spec/*.md
  preferentially, fall back to *.html only for wireframes/SVG/full
  human-readable context.

This is the user's pre-existing scaffolding that the previous commits
hadn't pulled in yet. Now tracked + enforced by hook.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>