skilllint 0.4.0

Static analysis linter for Claude Code plugins, skills, and agents

skilllint

Static analysis linter for AI agent plugins, skills, and agents — for Claude Code, Cursor, Codex, and any agentskills.io-compatible platform.

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What it does

skilllint validates the structure and content of AI agent files: plugins, skills, agents, and commands. It catches broken references, missing frontmatter, oversized skills, invalid hook configurations, and more — before they cause silent failures at runtime.

$ skilllint plugins/my-plugin

plugins/my-plugin/skills/my-skill/SKILL.md
  SK006  Token count 14823 exceeds recommended limit of 8192

plugins/my-plugin/agents/my-agent.md
  NR001  Namespace reference 'other-plugin:some-skill' — plugin directory not found

2 errors in 2 files

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Installation

pip install skilllint

Or with uv:

uv add skilllint          # add to a project
uv tool install skilllint # install as a global tool

Requires Python 3.11–3.14.

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Quick start

# Validate a plugin directory
skilllint plugins/my-plugin

# Validate a single skill file
skilllint plugins/my-plugin/skills/my-skill/SKILL.md

# Validate everything and show a summary
skilllint --show-summary plugins/

# Auto-fix issues where possible
skilllint --fix plugins/my-plugin

# Count tokens in any markdown file
skilllint --tokens-only .claude/CLAUDE.md

Exit codes: 0 = all checks passed · 1 = validation errors · 2 = usage error

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Pre-commit hook

Add to .pre-commit-config.yaml:

repos:
  - repo: https://github.com/bitflight-devops/agentskills-linter
    rev: v0.1.0
    hooks:
      - id: skilllint

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Platform support

skilllint ships with adapters for three platforms and supports third-party adapters via Python entry points:

Platform	Adapter ID	Bundled
Claude Code	claude-code	✓
Cursor	cursor	✓
OpenAI Codex	codex	✓
OpenCode, Gemini, and others	—	via entry points

Restrict validation to one platform:

skilllint --platform claude-code plugins/my-plugin

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What gets validated

Code	Category	Description
FM001–FM010	Frontmatter	Required fields, valid values, schema compliance
SK001–SK009	Skill	Description quality, token limits, complexity, internal links
PL001–PL005	Plugin	Structure, registration, subprocess safety
HK001–HK005	Hook	Script existence, configuration validity
NR001–NR002	Namespace refs	Cross-plugin skill/agent/command references
PR001–PR005	Registration	Plugin manifest correctness

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CLI reference

Usage: skilllint [OPTIONS] [PATHS]...

Options:
  --check            Validate only, don't auto-fix
  --fix              Auto-fix issues where possible
  --verbose, -v      Show detailed output including info messages
  --no-color         Disable colour output for CI
  --tokens-only      Output only the integer token count
  --show-progress    Show per-file PASSED/FAILED status
  --show-summary     Show validation summary panel at the end
  --filter TEXT      Glob pattern to match files within a directory
  --filter-type TEXT Shortcut: skills | agents | commands
  --platform TEXT    Restrict to a specific platform adapter
  --help             Show this message and exit

All four command names are aliases for the same tool:

skilllint   # primary
agentlint   # alias
pluginlint  # alias
skillint    # alias

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Third-party adapters

Register a custom platform adapter via Python entry points in your pyproject.toml:

[project.entry-points."skilllint.adapters"]
my-platform = "my_package.adapter:MyPlatformAdapter"

Your adapter must implement the AdapterProtocol interface from skilllint.adapters.protocol.

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Links

• GitHub repository
• Issue tracker
• PyPI
• agentskills.io

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License

MIT