Skill Evaluator Skill for Claude

Skill Evaluator (WIP)

Evaluates skills against Anthropic's official best practices for agent skill authoring. Produces structured evaluation reports with scores and actionable recommendations.

Quick Start

• Read the skill's SKILL.md and understand its purpose
• Run automated validation: scripts/validate_skill.py <skill-path>
• Perform manual evaluation against criteria below
• Generate evaluation report with scores and recommendations

Evaluation Workflow

Step 1: Automated Validation

Run the validation script first:

scripts/validate_skill.py <path/to/skill>

This checks:

• SKILL.md exists with valid YAML frontmatter
• Name follows conventions (lowercase, hyphens, max 64 chars)
• Description is present and under 1024 chars
• Body is under 500 lines
• File references are one-level deep

Step 2: Manual Evaluation

Evaluate each dimension and assign a score (1-5):

A. Naming (Weight: 10%)

| Score | Criteria |

|-------|----------|

| 5 | Gerund form (-ing), clear purpose, memorable |

| 4 | Descriptive, follows conventions |

| 3 | Acceptable but could be clearer |

| 2 | Vague or misleading |

| 1 | Violates naming rules |

Rules: Max 64 chars, lowercase + numbers + hyphens only, no reserved words (anthropic, claude), no XML tags.

Good: processing-pdfs, analyzing-spreadsheets, building-dashboards

Bad: pdf, my-skill, ClaudeHelper, anthropic-tools

B. Description (Weight: 20%)

| Score | Criteria |

|-------|----------|

| 5 | Clear functionality + specific activation triggers + third person |

| 4 | Good description with some triggers |

| 3 | Adequate but missing triggers or vague |

| 2 | Too brief or unclear purpose |

| 1 | Missing or unhelpful |

Must include: What the skill does AND when to use it.

Good: "Extracts text from PDFs. Use when working with PDF documents for text extraction, form parsing, or content analysis."

Bad: "A skill for PDFs." or "Helps with documents."

C. Content Quality (Weight: 30%)

| Score | Criteria |

|-------|----------|

| 5 | Concise, assumes Claude intelligence, actionable instructions |

| 4 | Generally good, minor verbosity |

| 3 | Some unnecessary explanations or redundancy |

| 2 | Overly verbose or confusing |

| 1 | Bloated, explains obvious concepts |

Ask: "Does Claude really need this explanation?" Remove anything Claude already knows.

D. Structure & Organization (Weight: 25%)

| Score | Criteria |

|-------|----------|

| 5 | Excellent progressive disclosure, clear navigation, optimal length |

| 4 | Good organization, appropriate file splits |

| 3 | Acceptable but could be better organized |

| 2 | Poor organization, missing references, or bloated SKILL.md |

| 1 | No structure, everything dumped in SKILL.md |

Check:

• SKILL.md under 500 lines
• References are one-level deep (no nested chains)
• Long reference files (>100 lines) have table of contents
• Uses forward slashes in all paths

E. Degrees of Freedom (Weight: 10%)

| Score | Criteria |

|-------|----------|

| 5 | Perfect match: high freedom for flexible tasks, low for fragile operations |

| 4 | Generally appropriate freedom levels |

| 3 | Acceptable but could be better calibrated |

| 2 | Mismatched: too rigid or too loose |

| 1 | Completely wrong freedom level for the task type |

Guideline:

• High freedom (text): Multiple valid approaches, context-dependent
• Medium freedom (parameterized): Preferred pattern exists, some variation OK
• Low freedom (specific scripts): Fragile operations, exact sequence required

F. Anti-Pattern Check (Weight: 5%)

Deduct points for each anti-pattern found:

• [ ] Too many options without clear recommendation (-1)
• [ ] Time-sensitive information with date conditionals (-1)
• [ ] Inconsistent terminology (-1)
• [ ] Windows-style paths (backslashes) (-1)
• [ ] Deeply nested references (more than one level) (-2)
• [ ] Scripts that punt error handling to Claude (-1)
• [ ] Magic numbers without justification (-1)

Step 3: Generate Report

Use this template:

# Skill Evaluation Report: [skill-name]

## Summary
- **Overall Score**: X.X/5.0
- **Recommendation**: [Ready for publication / Needs minor improvements / Needs major revision]

## Dimension Scores
| Dimension | Score | Weight | Weighted |
|-----------|-------|--------|----------|
| Naming | X/5 | 10% | X.XX |
| Description | X/5 | 20% | X.XX |
| Content Quality | X/5 | 30% | X.XX |
| Structure | X/5 | 25% | X.XX |
| Degrees of Freedom | X/5 | 10% | X.XX |
| Anti-Patterns | X/5 | 5% | X.XX |
| **Total** | | 100% | **X.XX** |

## Strengths
- [List 2-3 things done well]

## Areas for Improvement
- [List specific issues with actionable fixes]

## Anti-Patterns Found
- [List any anti-patterns detected]

## Recommendations
1. [Priority 1 fix]
2. [Priority 2 fix]
3. [Priority 3 fix]

## Pre-Publication Checklist
- [ ] Description is specific with activation triggers
- [ ] SKILL.md under 500 lines
- [ ] One-level-deep file references
- [ ] Forward slashes in all paths
- [ ] No time-sensitive information
- [ ] Consistent terminology
- [ ] Concrete examples provided
- [ ] Scripts handle errors explicitly
- [ ] All configuration values justified
- [ ] Required packages listed
- [ ] Tested with Haiku, Sonnet, Opus

Score Interpretation

| Score Range | Rating | Action |

|-------------|--------|--------|

| 4.5 - 5.0 | Excellent | Ready for publication |

| 4.0 - 4.4 | Good | Minor improvements recommended |

| 3.0 - 3.9 | Acceptable | Several improvements needed |

| 2.0 - 2.9 | Needs Work | Major revision required |

| 1.0 - 1.9 | Poor | Fundamental redesign needed |

References

• references/evaluation-criteria.md - Detailed evaluation criteria with examples
• references/scoring-rubric.md - Complete scoring rubric and edge cases

Examples

See evaluations/ for example evaluation scenarios.