Frontmatter.

YAML block — every page in wiki/

The eight fields every page carries, plus a few type-specific extras. Frontmatter is the machine-readable contract that lets lint.py and check-drift.py notice when pages drift from their sources.

The eight required fields

• type One of incident, service, root-cause, concept, owner. Determines the page's shape and which extras apply.
• name Human-readable name. Free text — used in the index listings.
• status stub · draft · reviewed. The lifecycle marker.
• owner Team slug. Write unknown if missing — never invent.
• sources List of paths under raw/ this page draws from.
• source_hashesMap of path → SHA-256. Never hand-edit — managed by tools/check-drift.py --update.
• tags Kebab-case, no spaces. Reuse existing tags before inventing new ones — check index.md for the current vocabulary.
• last_updatedDate of the most recent material change. Don't bump for whitespace edits.

Type-specific extras

• incident date, severity, duration_minutes, services, root_causes
• service upstream, downstream, incidents
• root-cause incidents, services
• concept (none beyond the required eight)
• owner services, incidents

What it looks like in a real file

---
type: incident
name: 2026-03-14 checkout latency spike
date: 2026-03-14
severity: SEV2
duration_minutes: 47
status: reviewed
owner: payments-team
services: [checkout-api, payments-db]
root_causes: [connection-pool-exhaustion]
sources:
  - raw/postmortems/2026-03-14-checkout.md
source_hashes:                                       # NEVER hand-edit
  raw/postmortems/2026-03-14-checkout.md: <sha256>     # run tools/check-drift.py --update
tags: [latency, database, capacity]
last_updated: 2026-04-26
---

Rules

1. All eight required fields appear on every page, in any order. Missing fields fail lint.
2. source_hashes is managed by tooling — after every ingest, run tools/check-drift.py --update.
3. Reuse existing tags before inventing new ones. The index is the canonical tag vocabulary.
4. Unknown owner is unknown, not blank. The wiki tracks unknowns explicitly so they don't get forgotten.
5. Frontmatter lists (e.g. services: [checkout-api]) resolve as wiki-links — the basename must match a real page or a stub.