The linter's main job - frontmatter keys, allowed-tools targets, the
command title rule - had zero assertions; deleting the missing-
allowed-tools error left the suite green. The fixture's yaml stub now
parses the flat frontmatter the fixtures write instead of returning a
canned mapping, and four new cases pin both check functions.
Mutation-verified against the real linter. Review finding F23
(2026-08-19).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Valid JSON such as [] or {"permissions": []} caused lint_skills.py to raise AttributeError because it assumed both values were objects.
Validate the top-level settings value and permissions object before reading nested keys. Malformed settings now produce clear lint errors and exit 1 without a traceback.
Add subprocess regression tests covering invalid JSON, malformed root values, invalid permissions values, and non-list permissions.allow values.
