mif-frontmatter

Shared substrate for every genre skill in this suite. It governs the YAML frontmatter that makes a document a MIF unit: a block that projects to the canonical JSON-LD and validates fail-closed against https://mif-spec.dev/schema/.

The "one artifact, two readers" contract

A MIF doc exists in two interconvertible forms — human-readable markdown (frontmatter + body) and machine-readable JSON-LD (the schema-checked canonical object). Authoring is bidirectional and the round-trip is lossless; see the mif-validate skill for the tooling.

Whenever a level, floor, or the type field itself comes up — deciding what level a document can claim, explaining the L1 floor, or drafting frontmatter — state the type enum explicitly (see the L1 row below). It's a hard constraint on an L1 field, not an implementation detail to leave implicit, so surface it every time L1 is discussed, not only when actually writing the YAML. For what distinguishes the three values and how to choose one before drafting, see Documentation Taxonomy — the canonical source for this enum; don't restate its definitions here.

Level floors (attempt the highest the context supports)

Field projection (markdown frontmatter -> JSON-LD)

• id -> @id (auto-prefixed urn:mif: if not already a URN). MIF 1.4.0+ requires @id to be urn:mif:<uuid>, so id MUST be a UUID: a slug such as prd-saved-carts fails the schema. Mint a random UUIDv4 for a new document; to derive a stable id from an existing slug, use UUIDv5 in the MIF namespace, uuid5(uuid5(NAMESPACE_URL, "https://mif-spec.dev"), slug), the same derivation MIF's migration script and mif-rs use. A relationship target naming another concept by URN uses that concept's urn:mif:<uuid>; a bundle-relative path (/semantic/policy.md) is the RECOMMENDED target for a concept in the same bundle.
• type -> conceptType; MUST be one of semantic, episodic, procedural (see Documentation Taxonomy for what each means and how to pick one). @type is always Concept. The document genre (adr, tutorial, runbook…) lives in namespace/tags, not in type.
• created -> created (ISO-8601 date-time)
• body -> content
• every other field passes through verbatim (it must be a valid MIF property or an open extension key).

Grade-down rule (never fabricate)

Attempt the highest level the drafting context supports, field by field. If a level's required field cannot be populated from real input (no citations -> no L3; no review cadence -> omit temporal), drop to the next lower level rather than writing a placeholder. Never emit an empty or unresolved-placeholder MIF field. This helper proposes frontmatter; mif-validate disposes.

Minimal L1 example

---
id: 7b3c1e90-5a2f-4c8d-9e10-2f6a4b8c1d3e
type: semantic
created: 2026-06-29T10:30:00Z
---