javascript-expert
Expert JavaScript developer specializing in modern ES6+ features, async patterns, Node.js, and browser APIs. Use when building JavaScript applications, optimizing performance, handling async operations, or implementing secure JavaScript code.
Install with Tessl CLI
npx tessl i github:martinholovsky/claude-skills-generator --skill javascript-expert70
Does it follow best practices?
If you maintain this skill, you can automatically optimize it using the tessl CLI to improve its score:
npx tessl skill review --optimize ./path/to/skillValidation for skill structure
Discovery
82%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This description has good completeness with an explicit 'Use when' clause and decent trigger term coverage for JavaScript developers. However, it uses role-based framing ('Expert JavaScript developer specializing in') rather than action-based language, and lacks specific concrete actions like 'debug promises', 'refactor callbacks', or 'implement API calls'. The description would benefit from more action verbs and slightly more distinctive triggers.
Suggestions
Replace role-based framing with concrete actions: instead of 'Expert JavaScript developer specializing in', use 'Writes, debugs, and refactors JavaScript code using modern ES6+ features'
Add more specific action verbs to improve specificity: 'handles promises, implements async/await patterns, builds Node.js servers, interacts with DOM and browser APIs'
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Names the domain (JavaScript) and mentions areas like 'ES6+ features, async patterns, Node.js, browser APIs' but uses role-based framing ('Expert JavaScript developer specializing in') rather than listing concrete actions. No specific verbs describing what it actually does. | 2 / 3 |
Completeness | Explicitly answers both what (JavaScript development with ES6+, async patterns, Node.js, browser APIs) and when ('Use when building JavaScript applications, optimizing performance, handling async operations, or implementing secure JavaScript code'). | 3 / 3 |
Trigger Term Quality | Good coverage of natural terms users would say: 'JavaScript', 'ES6+', 'async', 'Node.js', 'browser APIs', 'performance', 'async operations'. These are terms developers naturally use when seeking JavaScript help. | 3 / 3 |
Distinctiveness Conflict Risk | While JavaScript-specific, terms like 'building applications', 'optimizing performance', and 'secure code' could overlap with general coding skills or other language-specific skills. The JavaScript focus helps but isn't maximally distinctive. | 2 / 3 |
Total | 10 / 12 Passed |
Implementation
55%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill provides excellent actionable code examples and clear TDD workflow, but is severely bloated with unnecessary explanations of concepts Claude already knows. The content would benefit greatly from being split into multiple files (patterns, security, testing) with SKILL.md serving as a concise overview with navigation links.
Suggestions
Remove sections 1-3 entirely (Overview, Core Principles, Core Responsibilities) - these explain concepts Claude already knows and add no actionable value
Extract implementation patterns (section 5-6) into a separate PATTERNS.md file and reference it from the main skill
Extract security standards (section 7) into a separate SECURITY.md file
Reduce the main SKILL.md to a quick-start TDD workflow example and navigation links to detailed reference files
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | Extremely verbose at ~800+ lines. Explains concepts Claude already knows (what ES6 features are, what promises are, basic programming concepts). Contains extensive lists of expertise areas and principles that don't add actionable value. | 1 / 3 |
Actionability | Provides fully executable, copy-paste ready code examples throughout. Every pattern includes working JavaScript code with clear before/after comparisons (dangerous vs safe). Test examples are complete and runnable. | 3 / 3 |
Workflow Clarity | TDD workflow is clearly sequenced with explicit steps (write failing test → implement minimum → refactor → verify). Includes validation commands and checklists for each phase. The multi-phase checklist provides clear verification checkpoints. | 3 / 3 |
Progressive Disclosure | Monolithic wall of text with no references to external files. All content is inline despite being far too long for a single skill file. No navigation structure or links to separate reference materials for patterns, security, or testing. | 1 / 3 |
Total | 8 / 12 Passed |
Validation
75%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 12 / 16 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
skill_md_line_count | SKILL.md is long (1137 lines); consider splitting into references/ and linking | Warning |
metadata_version | 'metadata' field is not a dictionary | Warning |
license_field | 'license' field is missing | Warning |
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
Total | 12 / 16 Passed | |
- Reviewed
Table of Contents
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