knownasnaffy Skill Linter & Advisor
Analyze SKILL.md files against Claude Code Skills best practices and provide actionable feedback.
Analysis Process
- Read the SKILL.md file - Load the complete content
- Parse frontmatter - Validate YAML structure and required fields
- Check content structure - Verify best practices for the markdown body
- Compare against patterns - Match against known good Skill patterns
- Generate report - Provide structured feedback with severity levels
Validation Checklist
Frontmatter (YAML Header)
| Check | Severity | Description |
|---|---|---|
Has --- delimiters |
🔴 Critical | Must have opening and closing --- |
| Valid YAML syntax | 🔴 Critical | YAML must parse without errors |
Has name field |
🟡 Warning | Defaults to directory name, but explicit is better |
Has description |
🔴 Critical | Required for auto-trigger to work |
| Description quality | 🟡 Warning | Should be specific, mention when to use |
disable-model-invocation |
🟢 Info | Only set if you want manual-only |
user-invocable |
🟢 Info | Set to false to hide from / menu |
allowed-tools |
🟡 Warning | Specify if Skill needs specific tools |
model override |
🟢 Info | Only if you need specific model |
context: fork |
🟢 Info | Use for long-running or isolated tasks |
agent with context |
🟢 Info | Required when context: fork |
Content Structure
| Check | Severity | Description |
|---|---|---|
| Has clear title/heading | 🟡 Warning | First line should indicate purpose |
| Has process/steps | 🟡 Warning | Skills should have actionable steps |
| Has output format | 🟡 Warning | Define expected output structure |
| Uses specific language | 🟡 Warning | Avoid vague terms like "etc", "etc." |
| Has examples | 🟢 Info | Concrete examples improve reliability |
| Has constraints/guardrails | 🟢 Info | Define what NOT to do |
| Appropriate length | 🟡 Warning | Too short (<100 words) or too long (>2000) |
Common Issues
| Issue | Severity | Fix |
|---|---|---|
| Missing description | 🔴 Critical | Add description explaining when to trigger |
| Description too vague | 🟡 Warning | Be specific about use cases |
| No clear output format | 🟡 Warning | Add expected output structure |
| Missing tool declarations | 🟡 Warning | Add allowed-tools if using tools |
| Too many responsibilities | 🟡 Warning | Split into multiple focused Skills |
| Hardcoded paths | 🟡 Warning | Use variables or relative paths |
| No error handling guidance | 🟢 Info | Add what to do when things go wrong |
Output Format
# Skill Analysis Report
## File: {filepath}
### Frontmatter Analysis
| Field | Status | Value | Notes |
|-------|--------|-------|-------|
| name | ✅/⚠️/❌ | {value} | {feedback} |
| description | ✅/⚠️/❌ | {value} | {feedback} |
| ... | | | |
**Frontmatter Score:** X/10
### Content Analysis
| Check | Status | Notes |
|-------|--------|-------|
| Has clear purpose | ✅/⚠️/❌ | {feedback} |
| Actionable steps | ✅/⚠️/❌ | {feedback} |
| Output format defined | ✅/⚠️/❌ | {feedback} |
| Has examples | ✅/⚠️/❌ | {feedback} |
| Appropriate length | ✅/⚠️/❌ | {word_count} words |
**Content Score:** X/10
### Issues Found
#### 🔴 Critical (Must Fix)
1. {issue description} → {fix suggestion}
#### 🟡 Warnings (Should Fix)
1. {issue description} → {fix suggestion}
#### 🟢 Suggestions (Nice to Have)
1. {issue description} → {fix suggestion}
### Overall Assessment
**Total Score:** X/10
**Verdict:**
- ✅ Excellent - Ready to use
- 🟡 Good - Minor improvements suggested
- ⚠️ Needs Work - Address warnings before using
- ❌ Critical Issues - Must fix before using
### Recommended Actions
1. {action item}
2. {action item}
3. {action item}
### Improved Version (Optional)
If significant improvements are needed, provide a rewritten SKILL.md:
```yaml
---
# improved frontmatter
---
# Improved content...
## Skill Patterns Reference
### Pattern 1: Checklist/Task Skill
For: Code review, testing, validation tasks
Structure:
- Clear trigger description
- Step-by-step process
- Checklist categories
- Severity ratings
- Structured output format
### Pattern 2: Generator Skill
For: Documentation, commit messages, reports
Structure:
- Input requirements
- Analysis steps
- Template/format specification
- Examples
- Constraints
### Pattern 3: Explorer/Research Skill
For: Code exploration, debugging, analysis
Structure:
- Context gathering (!commands)
- Investigation steps
- What to look for
- How to present findings
### Pattern 4: Workflow Skill
For: Multi-step processes, releases, deployments
Structure:
- Prerequisites check
- Sequential steps
- Validation points
- Rollback guidance
## Examples of Good Descriptions
✅ **Good:**
- "Perform a thorough code review following the team checklist. Use when reviewing code changes, pull requests, or when the user asks for a code review."
- "Generate API documentation from source code. Use when the user asks to document an API endpoint, route handler, or controller."
- "Create a standardized git commit message following Conventional Commits format. Use when the user asks to commit or create a commit message."
❌ **Bad:**
- "Does code review" (too vague)
- "Helps with documentation" (when?)
- "A skill for git" (too broad)
## Examples of Good Output Formats
✅ **Good:**
```markdown
## Output Format
Structure your review as:
**Summary**
[One-paragraph overall assessment]
**Critical Issues**
[Must fix before merging]
**Approved?**
[YES / NO / YES WITH CONDITIONS]
❌ Bad:
Just give me a review of the code.