The universal quality standard for AI agent skills. Evaluate any SKILL.md — from skills.sh, ClawHub, GitHub, or your local machine.

✨ Features

• 🎯 Comprehensive Evaluation: 7 Anthropic-aligned scoring categories with weighted importance
• 🎨 Multiple Output Formats: Terminal (colorful), JSON, and Markdown reports
• 🔍 Deterministic Analysis: Reliable, reproducible scoring without requiring API keys
• 📋 Detailed Feedback: Specific findings and actionable recommendations
• ⚡ Fast & Reliable: Built with TypeScript for speed and reliability
• 🌍 Cross-Platform: Works on Windows, macOS, and Linux
• 🐙 GitHub Integration: Score skills directly from GitHub repositories
• 📊 Batch Mode: Compare multiple skills with a summary table
• 🗣️ Verbose Mode: See all findings, not just truncated summaries

📦 Installation

Global Installation (Recommended)

npm install -g skillscore

Local Installation

npm install skillscore
npx skillscore ./my-skill/

From Source

git clone https://github.com/joeynyc/skillscore.git
cd skillscore
npm install
npm run build
npm link

🚀 Quick Start

Evaluate a skill directory:

skillscore ./my-skill/

📖 Usage Examples

Basic Usage

# Evaluate a skill
skillscore ./skills/my-skill/

# Evaluate with verbose output (shows all findings)
skillscore ./skills/my-skill/ --verbose

GitHub Integration

# Full GitHub URL (always recognized)
skillscore https://github.com/FrancyJGLisboa/agent-skill-creator

# GitHub shorthand (requires -g/--github flag)
skillscore -g FrancyJGLisboa/agent-skill-creator

Output Formats

# JSON output
skillscore ./skills/my-skill/ --json

# Markdown report
skillscore ./skills/my-skill/ --markdown

# Save to file
skillscore ./skills/my-skill/ --output report.md
skillscore ./skills/my-skill/ --json --output score.json

Batch Mode

# Compare multiple skills (auto-enters batch mode)
skillscore ./skill1 ./skill2 ./skill3

# Explicit batch mode flag
skillscore ./skill1 ./skill2 --batch

# Compare GitHub skills
skillscore -g user/repo1/skill1 user/repo2/skill2 --json

Utility Commands

# Show version
skillscore --version

# Get help
skillscore --help

📊 Example Output

Terminal Output

📊 SKILLSCORE EVALUATION REPORT
============================================================

📋 Skill: weather-fetcher
   Fetches current weather data for any city when the user asks for forecasts or conditions.
   Path: ./weather-skill

🎯 OVERALL SCORE
   A- - 92.0% (9.2/10.0 points)

📝 CATEGORY BREAKDOWN
------------------------------------------------------------
Identity & Metadata ████████████████████ 100.0%
   YAML frontmatter with valid name/description, proper format, not vague
   Score: 10/10 (weight: 20%)
   ✓ Frontmatter name: "weather-fetcher" (+2)
   ✓ Name format valid (lowercase-hyphen, ≤64 chars) (+2)
   ✓ Frontmatter description present (+2)
   ... 3 more findings

Clarity & Instructions ██████████████████░░ 90.0%
   Workflow steps, consistent terminology, templates/examples, degrees of freedom
   Score: 9/10 (weight: 15%)
   ✓ Has structured workflow steps (numbered lists or checklists) (+3)
   ✓ Consistent terminology throughout (+2)
   ✓ 4 code blocks with templates/examples (+2)
   ... 2 more findings (use --verbose to see all)

Safety & Security ██████████████░░░░░░ 70.0%
   No destructive commands without confirmation, no secret exfil, no privilege escalation
   Score: 7/10 (weight: 15%)
   ✓ No dangerous destructive commands found (+3)
   ✓ No secret exfiltration risk detected (+2)
   ⚠ Privilege escalation with justification: sudo (+1)

📈 SUMMARY
------------------------------------------------------------
✅ Strengths: Identity & Metadata, Conciseness, Clarity & Instructions, Routing & Scope
❌ Areas for improvement: Safety & Security

Generated: 3/13/2026, 1:37:51 AM

Batch Mode Output

📊 BATCH SKILL EVALUATION
Evaluating 3 skill(s)...

[1/3] Processing: ./weather-skill
✅ Completed

[2/3] Processing: ./file-backup
✅ Completed

[3/3] Processing: user/repo/skill
✅ Completed

📋 COMPARISON SUMMARY

Skill                          Grade  Score    Identity Routing Safety Status
weather-fetcher                A-     92.0%    100%     100%    70%    OK
file-backup                    B+     87.0%    90%      80%     90%    OK
data-processor                 A      94.0%    100%     100%    85%    OK

📈 BATCH SUMMARY
✅ Successful: 3
📊 Average Score: 91.0%

🏆 Scoring System

SkillScore evaluates skills across 7 weighted categories aligned with Anthropic's official skill documentation:

| Category | Weight | Description | |----------|--------|-------------| | Identity & Metadata | 20% | YAML frontmatter name/description, lowercase-hyphen format, not vague | | Conciseness | 15% | Body ≤500 lines, progressive disclosure, no over-explaining basics | | Clarity & Instructions | 15% | Workflow steps, consistent terminology, templates/examples, degrees of freedom | | Routing & Scope | 15% | WHAT+WHEN description, negative routing, domain vocabulary, third-person voice | | Robustness | 10% | Error handling in code blocks, validation steps, dependency verification | | Safety & Security | 15% | No destructive commands, proximity-based secret exfil detection, no privilege escalation | | Portability & Standards | 10% | No platform-specific paths, MCP tool format, no time-sensitive info, relative paths |

Scoring Methodology

Each category is scored from 0-10 points based on specific criteria:

• Identity & Metadata: Validates YAML frontmatter name (lowercase-hyphen, ≤64 chars, no reserved words) and description (≤1024 chars, third person, no XML tags), rejects vague names/descriptions
• Conciseness: Enforces the 500-line body limit, checks for progressive disclosure via file references, flags over-explaining basics Claude already knows
• Clarity & Instructions: Checks for numbered steps or checklists, consistent terminology (no synonym pairs used interchangeably), code block examples, and a mix of imperative ("must") and flexible ("consider") guidance
• Routing & Scope: Validates description has action verbs + trigger conditions, negative routing examples ("don't use when..."), domain-specific vocabulary, and third-person voice
• Robustness: Scans code blocks for error handling (try/catch, ||, set -e), validates dependency verification commands (--version, command -v), flags magic constants
• Safety & Security: Proximity-based secret exfil detection (secrets + network within 5 lines), destructive command scanning with confirmation check, privilege escalation detection, unbounded loop detection
• Portability & Standards: Flags Windows-style paths, hardcoded absolute paths, validates MCP tool ServerName:tool_name format, detects time-sensitive info (dates, pinned versions)

v2.0.0: Anthropic-Aligned Rubric

Complete scoring redesign replacing the original 8 generic categories with 7 categories aligned to Anthropic's official skill documentation:

| Change | Details | |--------|---------| | Frontmatter validation | Skills must have YAML frontmatter with name and description fields | | Name format checks | Names must be lowercase-hyphen (^[a-z0-9][a-z0-9-]*$), ≤64 chars, no reserved words | | Conciseness scoring | New category enforcing 500-line limit, progressive disclosure, no over-explaining | | Third-person detection | Descriptions should use third-person voice, not "I/We/My" | | Proximity-based exfil | Secret + network pattern detection within 5-line proximity windows | | MCP format validation | MCP tool references must use ServerName:tool_name format | | Time-sensitive detection | Flags specific dates, "as of", and pinned version references |

Grade Scale

| Grade | Score Range | Description | |-------|-------------|-------------| | A+ | 97-100% | Exceptional quality | | A | 93-96% | Excellent | | A- | 90-92% | Very good | | B+ | 87-89% | Good | | B | 83-86% | Above average | | B- | 80-82% | Satisfactory | | C+ | 77-79% | Acceptable | | C | 73-76% | Fair | | C- | 70-72% | Needs improvement | | D+ | 67-69% | Poor | | D | 65-66% | Very poor | | D- | 60-64% | Failing | | F | 0-59% | Unacceptable |

📁 What Makes a Good Skill?

Required Structure

my-skill/
├── SKILL.md           # Main skill definition (REQUIRED)
├── README.md          # Documentation (recommended)
├── package.json       # Dependencies (if applicable)
├── scripts/           # Executable scripts
│   ├── setup.sh
│   └── main.py
└── examples/          # Usage examples
    └── example.md

SKILL.md Template

---
name: my-awesome-skill
description: Performs [specific task] when the user needs to [trigger condition].
---

# My Awesome Skill

Performs [specific task] using [specific tools/inputs].

## When to Use

Use this skill when you need to [specific task] with [specific tools/inputs].

## When NOT to Use

Don't use this skill when:
- The task is [alternative scenario] — use [other skill] instead
- You need [different capability]

## Dependencies

- Tool 1: Installation instructions (`tool --version` to verify)
- API Key: How to obtain and configure
- Environment: OS requirements

## Workflow

1. Step-by-step instructions
2. Specific commands to run
3. Expected outputs

- [ ] Verify dependencies
- [ ] Confirm configuration

## Output

Results are written to `./output/` as JSON files.

## Error Handling

You must always validate output. Consider retrying on transient failures.

```bash
if ! result=$(./scripts/main.py --input "data"); then
  echo "Error: processing failed"
  exit 1
fi

Examples

Example Output

{
  "status": "success",
  "result": "Example of what the skill produces"
}

Limitations

• Known constraints
• Platform-specific notes
• Edge cases

See docs/advanced.md for more details.

## 🔧 API Usage

Use SkillScore programmatically in your Node.js projects:

```typescript
import { SkillParser, SkillScorer, TerminalReporter } from 'skillscore';
import type { Reporter, SkillScore } from 'skillscore';

const parser = new SkillParser();
const scorer = new SkillScorer();
const reporter: Reporter = new TerminalReporter();

async function evaluateSkill(skillPath: string): Promise<SkillScore> {
  const skill = await parser.parseSkill(skillPath);
  const score = await scorer.scoreSkill(skill);
  const report = reporter.generateReport(score);

  console.log(report);
  return score;
}

All three reporters (TerminalReporter, JsonReporter, MarkdownReporter) implement the Reporter interface.

ParsedSkill Fields (v2.0)

The parser now extracts additional metadata used by the new scoring rubric:

interface ParsedSkill {
  // Existing fields
  skillPath: string;
  skillMdExists: boolean;
  skillMdContent: string;
  name: string;
  description: string;
  files: string[];
  metadata: Record<string, unknown>;
  structure: FileStructure;

  // New in v2.0
  frontmatter: Record<string, unknown>;    // YAML frontmatter (same ref as metadata)
  bodyContent: string;                      // SKILL.md after stripping frontmatter
  bodyLineCount: number;                    // Line count of body
  nameSource: 'frontmatter' | 'heading' | 'fallback';
  descriptionSource: 'frontmatter' | 'inline' | 'inferred' | 'none';
  referencedFiles: string[];               // Markdown links extracted from SKILL.md
}

🛠️ CLI Options

Usage: skillscore [options] <path...>

Arguments:
  path                   Path(s) to skill directory, GitHub URL, or shorthand

Options:
  -V, --version         Output the version number
  -j, --json            Output in JSON format
  -m, --markdown        Output in Markdown format
  -o, --output <file>   Write output to file
  -v, --verbose         Show ALL findings (not just truncated)
  -b, --batch           Batch mode for comparing multiple skills
  -g, --github          Treat shorthand paths as GitHub repos (user/repo/path)
  -h, --help           Display help for command

🧪 Testing

# Run all tests
npm test

# Run tests in watch mode
npm test

# Run tests once
npm run test:run

# Lint code
npm run lint

# Build project
npm run build

🤝 Contributing

We welcome contributions! Here's how to get started:

Development Setup

git clone https://github.com/joeynyc/skillscore.git
cd skillscore
npm install
npm run build
npm link

# Run in development mode
npm run dev ./test-skill/

# Build for production
npm run build

Running Tests

npm test

Submitting Changes

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Make your changes
4. Add tests for new functionality
5. Ensure all tests pass (npm test)
6. Lint your code (npm run lint)
7. Commit your changes (git commit -m 'Add amazing feature')
8. Push to the branch (git push origin feature/amazing-feature)
9. Open a Pull Request

Coding Standards

• Use TypeScript for all new code
• Follow existing code style (enforced by ESLint)
• Add tests for new features
• Update documentation for API changes
• Keep commits focused and descriptive

🐛 Troubleshooting

Common Issues

Error: "Path does not exist"

• Check for typos in the path
• Ensure you have permission to read the directory
• Verify the path points to a directory, not a file

Error: "No SKILL.md file found"

• Skills must contain a SKILL.md file
• Check if you're pointing to the right directory
• The file must be named exactly "SKILL.md"

Error: "Git is not available"

• Install Git to clone GitHub repositories
• macOS: xcode-select --install
• Ubuntu: sudo apt-get install git
• Windows: Download from git-scm.com

Scores seem too high/low

• Scoring is calibrated against real-world skills
• See the scoring methodology above
• Consider the specific criteria for each category

Getting Help

• 🐛 Report Issues
• 💬 Discussions
• 📚 Documentation

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• Inspired by the need for quality assessment in AI agent skills
• Built for the OpenClaw and Claude Code communities
• Thanks to all contributors and skill creators
• Scoring methodology aligned with Anthropic's official skill documentation

📊 Example Scores

Real-world skills scored with SkillScore v2.0:

• FrancyJGLisboa/agent-skill-creator: 83.5% (B) - Perfect identity & robustness, needs negative routing and trimming (617 lines)
• gapmiss/obsidian-plugin-skill: 52% (F) - No frontmatter, weak routing signals, missing structured workflow
• skill-creator (local): 86% (B) - Strong identity & conciseness (353 lines, 6 file refs), needs error handling in code blocks