SkillSeal

Test your Agent Skills before your agents do.

SKILL.md files can be syntactically valid and still be bad: a vague description that never routes correctly, an oversized file that eats context, a curl | sh buried in a code block, a hardcoded /Users/you/... path that only works on your machine. None of that shows up until an agent picks the wrong skill, or picks the right one and runs something it shouldn't.

SkillSeal is a local-first, offline-first CLI that lints, scores, and routing-tests SKILL.md files, so you catch that before an agent does. It's deliberately scoped to what's useful today: static linting across four categories, deterministic (LLM-optional) routing tests, and CI-friendly exit codes and JSON output. No dashboard, no registry, no cloud.

Installation

Requires Python 3.12+. Install from PyPI with uv, pipx, or pip:

uv tool install skillseal
# or: pipx install skillseal
# or: pip install skillseal

No install at all, one-off run:

uvx skillseal check ./skills

For local development, clone the repo instead:

git clone https://github.com/pespinel/skillseal
cd skillseal
uv sync

Quickstart

skillseal check examples
skillseal test examples
skillseal conflicts examples/conflicting-skills
skillseal diff old-version/ new-version/

(From a repo clone without installing, prefix these with uv run.)

All commands accept a path to a single SKILL.md file, a single skill directory, or a directory containing many skills (searched recursively).

See Commands for the full reference, or jump straight to Using it in CI.