frontmatter-guard

Detect and repair YAML frontmatter errors in brain pages.

Updated May 16, 2026
One-click install
npx skills add https://github.com/Morris-UTRUST/GBrain-knowledge --skill frontmatter-guard-morris-utrust
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: frontmatter-guard
Source: https://github.com/Morris-UTRUST/GBrain-knowledge/tree/main/skills/frontmatter-guard
Command: npx skills add https://github.com/Morris-UTRUST/GBrain-knowledge --skill frontmatter-guard-morris-utrust

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Validate and auto-repair YAML frontmatter on brain pages. Catches malformed pages before they enter the brain (missing closing ---, nested quotes, slug mismatches, null bytes, empty frontmatter, YAML parse failures). Wraps the gbrain frontmatter CLI for agent-driven workflows.

Core Features & Use Cases

  • Validation classes include: MISSING_OPEN, MISSING_CLOSE, YAML_PARSE, SLUG_MISMATCH, NULL_BYTES, NESTED_QUOTES, EMPTY_FRONTMATTER.
  • Auto-fix with .bak backups on demand; shares logic with gbrain doctor frontmatter_integrity; per-source audit reporting.
  • Use cases include pre-ingestion validation, CI pre-commit checks, and routine brain health audits.

Quick Start

Run the frontmatter audit across brain pages to detect and repair frontmatter issues.

Frequently Asked Questions about frontmatter-guard

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I validate YAML frontmatter in brain pages before ingestion?

You can validate YAML frontmatter by running an audit across brain pages to detect missing open/close markers, YAML parse failures, slug mismatches, null bytes, and nested quotes before the content enters the brain.

Can I automatically fix malformed frontmatter without losing the original content?

Yes, you can auto-fix malformed frontmatter on demand; the tool creates .bak backups of the original pages before applying any automated repairs to ensure your content is not lost.

What causes a slug mismatch error during a frontmatter audit?

A slug mismatch error occurs when the slug field inside the YAML frontmatter does not align with the expected page identifier, which this validation process identifies and optionally repairs automatically.

Do I need the gbrain frontmatter tooling to run frontmatter validation?

Yes, running frontmatter validation and auto-repair requires the gbrain frontmatter tooling, as the skill wraps its CLI to provide agent-driven workflows for detecting and fixing malformed pages.

What is the best way to check brain health for YAML parse failures and empty frontmatter?

The best way to check brain health is to run a per-source audit report that identifies validation classes like YAML_PARSE, EMPTY_FRONTMATTER, and NULL_BYTES, sharing logic with the gbrain doctor.

Can I use frontmatter validation as a CI pre-commit check?

Yes, frontmatter validation is designed for CI pre-commit checks, allowing you to catch malformed pages with missing closing markers or nested quotes before they are ingested into the brain.