skillsaw 0.4.2

A configurable linter for agent skills, plugins, and AI coding assistant context

skillsaw

A configurable, rule-based linter for agentskills.io skills, Claude Code plugins, and plugin marketplaces.

Note: This project was formerly named claudelint. If you're migrating, see Migrating from claudelint.

Features

• Context-Aware - Automatically detects agentskills repos, single plugins, and marketplaces
• Rule-Based - Enable/disable individual rules with configurable severity levels
• Extensible - Load custom rules from Python files
• Comprehensive - Validates skill format, plugin structure, metadata, command format, and more
• Containerized - Run via Docker for consistent, isolated linting
• Fast - Efficient validation with clear, actionable output

Installation

Via uvx (easiest - no install required)

uvx skillsaw
uvx skillsaw /path/to/skills

Via pip

pip install skillsaw

From source

git clone https://github.com/stbenjam/skillsaw.git
cd skillsaw
pip install -e .

Using Docker

docker pull ghcr.io/stbenjam/skillsaw:latest
docker run -v $(pwd):/workspace ghcr.io/stbenjam/skillsaw

Quick Start

# Lint current directory
skillsaw

# Lint specific directory
skillsaw /path/to/skills

# Verbose output
skillsaw -v

# Strict mode (warnings as errors)
skillsaw --strict

# Generate default config
skillsaw --init

# List all available rules
skillsaw --list-rules

Repository Types

skillsaw automatically detects your repository structure:

agentskills.io Skills

Standalone skill repositories following the agentskills.io specification:

my-skill/
├── SKILL.md              # Required: metadata + instructions
├── scripts/              # Optional: executable code
├── references/           # Optional: documentation
├── assets/               # Optional: templates, resources
├── evals/                # Optional: evaluation tests
│   └── evals.json
└── <any-dir>/            # Arbitrary directories allowed per spec

Skill collections (multiple skills in subdirectories) are also supported:

skills-repo/
├── skill-one/
│   └── SKILL.md
└── skill-two/
    └── SKILL.md

Standard discovery paths (.claude/skills/, .github/skills/, .agents/skills/) are checked automatically.

Single Plugin

my-plugin/
├── .claude-plugin/
│   └── plugin.json
├── commands/
│   └── my-command.md
├── skills/
│   └── my-skill/
│       └── SKILL.md
└── README.md

Marketplace (Multiple Plugins)

skillsaw supports multiple marketplace structures per the Claude Code specification:

Traditional Structure (plugins/ directory)

marketplace/
├── .claude-plugin/
│   └── marketplace.json
└── plugins/
    ├── plugin-one/
    │   ├── .claude-plugin/
    │   └── commands/
    └── plugin-two/
        ├── .claude-plugin/
        └── commands/

Flat Structure (root-level plugin)

marketplace/
├── .claude-plugin/
│   └── marketplace.json    # source: "./"
├── commands/
│   └── my-command.md
└── skills/
    └── my-skill/

Custom Paths and Mixed Structures

Plugins from plugins/, custom paths, and remote sources can coexist in one marketplace. Only local sources are validated.

Configuration

Create .skillsaw.yaml in your repository root:

rules:
  # agentskills rules (auto-enabled when skills are detected)
  agentskill-valid:
    enabled: auto
    severity: error

  agentskill-name:
    enabled: auto
    severity: error

  # Plugin structure rules
  plugin-json-required:
    enabled: true
    severity: error

  # 'auto' enables only for relevant repo types
  marketplace-registration:
    enabled: auto
    severity: error

# Load custom rules
custom-rules:
  - ./my-custom-rules.py

# Exclude patterns
exclude:
  - "**/node_modules/**"
  - "**/.git/**"

# Treat warnings as errors
strict: false

Generating Default Config

skillsaw --init

This creates .skillsaw.yaml with all builtin rules and their defaults.

Builtin Rules

agentskills.io

These rules validate skills against the agentskills.io specification. They auto-enable for agentskills repos, single plugins, and marketplaces whenever skills are detected.

Rule ID	Description	Default Severity
agentskill-valid	SKILL.md must have valid frontmatter with name and description	error (auto)
agentskill-name	Skill name must be lowercase with hyphens and match directory name	error (auto)
agentskill-description	Skill description should be meaningful and within length limits	warning (auto)
agentskill-structure	Skill directories should only contain recognized subdirectories (stricter than spec)	warning (disabled)
agentskill-evals	Validate evals/evals.json format when present	warning (auto)
agentskill-evals-required	Require evals/evals.json for each skill	warning (disabled)

Note: The agentskill-structure rule is disabled by default because the agentskills.io spec allows arbitrary directories inside a skill. Enable it and configure allowed_dirs if you want stricter validation:

rules:
  agentskill-structure:
    enabled: true
    allowed_dirs:
      - scripts
      - references
      - assets
      - evals
      - tests        # add your own

Plugin Structure

Rule ID	Description	Default Severity
plugin-json-required	Plugin must have .claude-plugin/plugin.json	error
plugin-json-valid	Plugin.json must be valid with required fields	error
plugin-naming	Plugin names should use kebab-case	warning
plugin-readme	Plugin should have a README.md file	warning

Command Format

Rule ID	Description	Default Severity
command-naming	Command files should use kebab-case	warning
command-frontmatter	Command files must have valid frontmatter	error
command-sections	Commands should have Name, Synopsis, Description, Implementation sections	warning
command-name-format	Command Name section should be plugin:command format	warning

Marketplace

Rule ID	Description	Default Severity
marketplace-json-valid	Marketplace.json must be valid JSON	error (auto)
marketplace-registration	Plugins must be registered in marketplace.json	error (auto)

Skills, Agents, Hooks

Rule ID	Description	Default Severity
skill-frontmatter	SKILL.md files should have frontmatter	warning
agent-frontmatter	Agent files must have valid frontmatter	error
hooks-json-valid	hooks.json must be valid with proper structure	error

MCP (Model Context Protocol)

Rule ID	Description	Default Severity
mcp-valid-json	MCP configuration must be valid JSON	error
mcp-prohibited	Plugins should not enable MCP servers	error (disabled)

Custom Rules

Create custom validation rules by extending the Rule base class:

from pathlib import Path
from typing import List
from skillsaw import Rule, RuleViolation, Severity, RepositoryContext

class NoTodoCommentsRule(Rule):
    @property
    def rule_id(self) -> str:
        return "no-todo-comments"

    @property
    def description(self) -> str:
        return "Command files should not contain TODO comments"

    def default_severity(self) -> Severity:
        return Severity.WARNING

    def check(self, context: RepositoryContext) -> List[RuleViolation]:
        violations = []
        for plugin_path in context.plugins:
            commands_dir = plugin_path / "commands"
            if not commands_dir.exists():
                continue
            for cmd_file in commands_dir.glob("*.md"):
                content = cmd_file.read_text()
                if "TODO" in content:
                    violations.append(
                        self.violation("Found TODO comment", file_path=cmd_file)
                    )
        return violations

Then reference it in .skillsaw.yaml:

custom-rules:
  - ./my_custom_rules.py

rules:
  no-todo-comments:
    enabled: true
    severity: warning

CI/CD Integration

GitHub Actions

name: Lint Agent Skills

on: [pull_request, push]

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v5

      - name: Set up Python
        uses: actions/setup-python@v6
        with:
          python-version: '3.x'

      - name: Install skillsaw
        run: pip install skillsaw

      - name: Run linter
        run: skillsaw --strict

Docker

docker run -v $(pwd):/workspace ghcr.io/stbenjam/skillsaw --strict

Exit Codes

• 0 - Success (no errors, or warnings only in non-strict mode)
• 1 - Failure (errors found, or warnings in strict mode)

Example Output

Linting: /path/to/skills-repo

Errors:
  ✗ ERROR [skills/my-skill/SKILL.md]: Name 'My Skill' must contain only lowercase letters, numbers, and hyphens
  ✗ ERROR [plugins/git/.claude-plugin/plugin.json]: Missing plugin.json

Warnings:
  ⚠ WARNING [skills/helper/SKILL.md]: Description exceeds 1024 characters (1087)
  ⚠ WARNING [plugins/utils]: Missing README.md (recommended)

Summary:
  Errors:   2
  Warnings: 2

Migrating from claudelint

This project was renamed from claudelint to skillsaw. To migrate:

1. Update your package: pip install skillsaw (instead of pip install claudelint)
2. Rename .claudelint.yaml to .skillsaw.yaml (the old name is still discovered as a fallback)
3. Update CLI usage: skillsaw (instead of claudelint)
4. Update imports in custom rules: from skillsaw import ... (the old from claudelint import ... still works)

The claudelint command still works as a shim but prints a deprecation warning.

Removed rules

The following rules from claudelint have been removed in skillsaw:

Rule ID	Reason
commands-dir-required	Claude Code now treats skills/ and commands/ as the same mechanism; requiring a commands/ directory is no longer meaningful
commands-exist	Same as above — plugins don't need to have commands

If your .skillsaw.yaml references these rule IDs, skillsaw will emit a warning about the unknown rule.

Development

# Run tests
pytest tests/ -v

# Format code
black src/ tests/

# Build Docker image
docker build -t skillsaw .

Contributing

Contributions welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Add tests for new functionality
4. Ensure all tests pass
5. Submit a pull request

License

Apache 2.0 - See LICENSE for details.

See Also

• agentskills.io Specification
• Claude Code Documentation
• Claude Code Plugins Reference
• AI Helpers Marketplace - Example marketplace using skillsaw

Support

• Issues: https://github.com/stbenjam/skillsaw/issues
• Discussions: https://github.com/stbenjam/skillsaw/discussions