# Frontmatter Repair

> Repair synthetic MDX frontmatter when title, description, or sidebar.order drift from the frontmatter contract. Use for files that follow the same observable patterns proven in the receipts; do not use on private transcripts, secret-bearing material, or arbitrary YAML.

- Skill: `learnprompt/frontmatter-repair` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add learnprompt/frontmatter-repair`
- Raw SKILL.md: https://api.skillmd.com/api/skills/learnprompt/frontmatter-repair/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: learnprompt (https://skillmd.com/u/learnprompt)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/learnprompt/frontmatter-repair

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Repair one synthetic MDX file at a time.

1. Read [the frontmatter contract](references/frontmatter-contract.md).
2. Run `node scripts/repair-frontmatter.mjs --file <path>`.
3. Only repair rules proven by the receipts:
   - title from the first H1
   - description from the opening paragraph’s first sentence
   - invalid `sidebar.order` to `999`
4. Preserve the body verbatim.
5. Leave already-valid files unchanged.
6. If the file contains private transcript material or secret markers, stop and escalate instead of repairing.