Check SKILL.md frontmatter before Codex rejects it.

Paste a SKILL.md file. This browser-only checker looks for unsupported top-level frontmatter keys, missing name/description, and common portability risks.

Codex-compatible top-level keys

name
description
allowed-tools
license
metadata

This is a pragmatic compatibility check, not an official validator. If your workflow needs cleanup, start with a free fit check.

Free fit check Example submission