quick_validate.py rejects all 7 plugin-dev skills over the version frontmatter key

skill-creator/scripts/quick_validate.py rejects every skill shipped by the plugin-dev and hookify plugins in this repository, because its allowlist omits the version frontmatter key those skills use.

Root cause

Line 42:

ALLOWED_PROPERTIES = {'name', 'description', 'license', 'allowed-tools', 'metadata', 'compatibility'}

Any other key is a hard rejection:

unexpected_keys = set(frontmatter.keys()) - ALLOWED_PROPERTIES
if unexpected_keys:
    return False, (f"Unexpected key(s) in SKILL.md frontmatter: ...")

Reproduction

Every one of these shipped skills declares version: in its frontmatter, and each is rejected:

plugin-dev/skills/agent-development
plugin-dev/skills/command-development
plugin-dev/skills/hook-development
plugin-dev/skills/mcp-integration
plugin-dev/skills/plugin-settings
plugin-dev/skills/plugin-structure
plugin-dev/skills/skill-development

That is 7 of 7 plugin-dev skills, plus hookify/skills/writing-rules.

Why it matters

Two official plugins in the same repository disagree about the skill frontmatter schema. A user who runs quick_validate.py over a skill modelled on the shipped examples is told their skill is invalid, and the examples themselves do not pass.

Suggested fix

Either add version to ALLOWED_PROPERTIES, or remove version: from the shipped skills, depending on which is intended. A single normative schema referenced by both plugins would prevent the pair drifting again.

Environment: Claude Code 2.1.219, Windows 11, Python 3.x.