Skillget

SkillCheck-Free

mcp
Security Audit
Pass
Health Pass
  • License — License: MIT
  • Description — Repository has a description
  • Active repo — Last push 0 days ago
  • Community trust — 17 GitHub stars
Code Pass
  • Code scan — Scanned 4 files during light audit, no dangerous patterns found
Permissions Pass
  • Permissions — No dangerous permissions requested
Purpose
This tool validates AI coding assistant skills against the open agentskills specification. It checks YAML frontmatter, trigger conditions, and instruction clarity to ensure compatibility across platforms like Claude Code, Cursor, and Claude Projects.

Security Assessment
The overall risk is rated as Low. The tool is essentially a static text checker that reads local SKILL.md files. It does not make external network requests, does not access sensitive user data, and does not require any dangerous system permissions. A light code audit of its shell scripts found no dangerous patterns, hidden executables, or hardcoded secrets.

Quality Assessment
The project appears healthy and legitimate. It is actively maintained (last updated today) and uses the highly permissive MIT license. It has garnered 17 GitHub stars, showing a baseline of community trust. The repository documentation is clear and straightforward, outlining exactly how to install and use the tool without requiring complex dependencies or opaque binaries.

Verdict
Safe to use.
SUMMARY

Validate Claude Code skills against the agentskills specification (Free tier)

README.md

SkillCheck Free

License: MIT
Claude Code
Claude Projects
Cursor

skillcheck passed

Validate AI coding assistant skills against the agentskills specification. Works with Claude Code, Claude Desktop/Web, and Cursor. Catch issues before your users do.

Why SkillCheck?

Agent Skills are now an open standard adopted by Claude Code, Cursor, and dozens of coding agents. Your skill needs to work everywhere and follow best practices.

SkillCheck validates:

  • Does the YAML frontmatter follow the spec?
  • Will it trigger when users actually need it?
  • Are the instructions clear and unambiguous?

Installation

Claude Code

Copy the skill-check folder to your Claude Code skills directory:

cp -r skill-check ~/.claude/skills/

Or clone directly:

git clone https://github.com/olgasafonova/SkillCheck-Free.git
cp -r SkillCheck-Free/skill-check ~/.claude/skills/

Claude Desktop/Web (Projects)

  1. Open claude.ai or Claude Desktop app
  2. Create a new Project (or open an existing one)
  3. Go to Project settings → Custom instructions
  4. Copy the contents of skill-check/SKILL.md (everything after the --- frontmatter)
  5. Paste into the custom instructions field

No file installation needed - the skill runs directly from your Project instructions.

Cursor

Copy the rule file to your project's .cursor/rules directory:

mkdir -p .cursor/rules
cp cursor-rules/skill-check.mdc .cursor/rules/

Or clone directly:

git clone https://github.com/olgasafonova/SkillCheck-Free.git
mkdir -p .cursor/rules
cp SkillCheck-Free/cursor-rules/skill-check.mdc .cursor/rules/

Usage

In Claude Code, Claude Desktop/Web, or Cursor, say any of:

  • "skillcheck my skill"
  • "check skill at path/to/SKILL.md"
  • "validate my skills"

Example Output

## SkillCheck Results: my-awesome-skill

### Summary
- Critical: 1 | Warnings: 2 | Suggestions: 3 | Passed: 44

### Critical Issues
**[1.2-desc-what]** Line 3: Description missing action verb
**Fix**: Start description with Create, Generate, Build, Convert, etc.

### Warnings
**[4.2-ambiguous-term]** Line 47: Vague term "several" found
**Fix**: Specify exact count or range

### Strengths
- Skill includes example section
- Skill documents prerequisites
- Description includes activation triggers

What It Checks

Structure (1.x)

Check What It Catches
1.1-name Invalid name format, reserved words
1.2-desc Missing or weak description (WHAT verb + WHEN trigger recommended)
1.3-tools Unknown or deprecated tool formats
1.4-category Invalid category format
1.9-xml XML angle brackets in frontmatter (prompt injection risk)
1.9-arg-hints Missing argument-hint in frontmatter when $ARGUMENTS is used
1.10-readme README.md inside skill folder (docs belong in SKILL.md)

Body (2.x)

Check What It Catches
2.1-lines File too long (500+ lines warning)
2.3-date Hardcoded dates that will go stale
2.4-empty Empty sections with no content
2.8-antipattern-format Anti-pattern sections using prose instead of tables/bullets
2.9-mcp-tool-unqualified Unqualified MCP tool names missing server prefix

Naming (3.x)

Check What It Catches
3.1-vague Generic names like "helper", "utils"
3.2-length Names too short or too long
3.3-single Single-word names lacking specificity
3.4-gerund Gerund naming ("writing-helper" instead of verb-noun)

Semantic (4.x)

Check What It Catches
4.1-contradiction Conflicting instructions
4.2-ambiguous Vague terms like "several", "appropriate"
4.3-output Output mentioned but no format specified
4.6-wisdom Generic advice/platitudes instead of actionable instructions
4.7-desc-workflow-steps Description summarizes workflow steps (causes agents to skip body)

Design Pattern Classification (19.x)

SkillCheck classifies each skill into one of five design patterns from the Google ADK taxonomy:

Pattern What It Means Example Skills
Reviewer Evaluates output against criteria skill-check, code-review
Generator Produces structured artifacts from templates linkedin-post, brand-assets
Inversion Asks user questions before acting grill-me, feature-scoping
Pipeline Chains multiple steps with checkpoints sift, tapestry
Tool Wrapper Wraps an API with context-aware instructions lmwtfy

Pro adds deep checks: validates pattern-specific requirements (criteria for Reviewers, output specs for Generators, etc.).

Quality Patterns (8.x) - Strengths

SkillCheck also recognizes good practices:

Check What It Recognizes
8.1 Has example section
8.2 Documents error handling or limitations
8.3 Description includes activation triggers
8.4 Specifies output format with examples
8.5 Uses structured instructions (numbered steps)
8.6 Documents prerequisites
8.7 Includes negative triggers to prevent over-triggering
8.8 Uses ${CLAUDE_SKILL_DIR} for portable path references

Severity Levels

Level Meaning Action
Critical Skill may not function Must fix
Warning Best practice violation Should fix
Suggestion Could be improved Nice to have
Strength Good practice detected Keep it up

Free vs Pro

Feature Free Pro
Structure validation Yes Yes
Body & naming checks Yes Yes
Semantic consistency Yes Yes
Quality patterns Yes Yes
Design Pattern Classification Detection Deep checks
Artifact Contract Validation - Yes
Trigger Collision Detection - Yes
Eval Kit (test prompt generation) - Yes
Anti-slop detection - Yes
Security scanning - Yes
Token budget analysis - Yes
WCAG accessibility - Yes
Enterprise readiness - Yes
Production readiness - Yes
Agent Readiness (L0-L3) - Yes
MCP server integration - Yes
CI/CD binary - Yes

Get Pro: getskillcheck.com

Prerequisites

  • Claude Code (or any AI assistant with file Read capability)
  • Works on macOS, Linux, Windows
  • No dependencies required

How It Works

SkillCheck Free is itself a skill/rule file. When you say "skillcheck", your AI assistant reads the validation rules and applies them to your target skill. No external API calls, no binaries - just your assistant following instructions.

Contributing

Found a bug or have a suggestion? Open an issue at github.com/olgasafonova/SkillCheck-Free/issues

Links

License

MIT - see LICENSE

Built by Olga Safonova

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