frontmatter-guard is agent-read markdown (skill) from lstr-1/skills: Injects the canonical vault frontmatter schema snippet into agent prompts before any vault-write task, preventing malformed YAML frontmatter in Obsidian notes. <example>Context: wave-executor is about to dispatch a vault-mirror agent that writes learning notes under ~/Projects/vault/40-learnings/. user: "dispatch vault-write agent" assistant: "Injecting frontmatter-guard snippet into agent prompt (vault scope detected). Required fields: id, type, created, updated. Enum type: note|daily|project|p.
Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.
What the file says
# Frontmatter-Guard Skill
> **Port note — `unverified` runtime.** This skill references runtime modules under
> `scripts/lib/*.mjs`. Those modules are NOT present in the source plugin directory `sex/`
> and were NOT ported. Every such reference is `unverified`: the agent MUST probe for the
> module at runtime and continue in degraded mode when it is absent. Do NOT assume the module
> exists. Affected modules in this skill: `scripts/lib/frontmatter-guard.mjs`.
> Project-instruction file resolution: `CLAUDE.md` and `AGENTS.md` (Codex CLI) are transparent aliases — see [skills/_shared/instruction-file-resolution.md](../_shared/instruction-file-resolution.md). Wherever this skill mentions `CLAUDE.md`, the alias rule applies.
## Purpose
vault-mirror and other vault-write agents frequently produce notes with missing or malformed YAML frontmatter — incorrect `type` enum values, missing `id`, wrong date formats. The resulting notes fail the vault-sync validator at session-end, causing hard-gate failures that interrupt the close flow.
…
Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.
GET https://markdownregistry.com/api/v1/artifacts/art_zm6ex3bzptcttezo
GET https://markdownregistry.com/api/v1/resolve?ref=lstr-1/skills/frontmatter-guard
GET https://markdownregistry.com/api/v1/blob/76ca35005a43dc40cfb4152a5c6b0bcca573518c62443648dabcbc03ff20706a
Your agent does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
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kanevry/session-orchestrator · .agents/skills/frontmatter-guard/SKILL.md · Injects the canonical vault frontmatter schema snippet into agent prompts before any vault-write task, preventing…
kanevry/session-orchestrator · skills/frontmatter-guard/SKILL.md · Injects the canonical vault frontmatter schema snippet into agent prompts before any vault-write task, preventing…
kanevry/session-orchestrator · .cursor/skills/frontmatter-guard/SKILL.md · Injects the canonical vault frontmatter schema snippet into agent prompts before any vault-write task, preventing…
kanevry/session-orchestrator · .codex-plugin/skills/frontmatter-guard/SKILL.md · Injects the canonical vault frontmatter schema snippet into agent prompts before any vault-write task, preventing…
