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Writes, debugs, and refactors JavaScript code using modern ES2023+ features, async/await patterns, ESM module systems, and Node.js APIs. Use when building vanilla JavaScript applications, implementing Promise-based async flows, optimising browser or Node.js performance, working with Web Workers or Fetch API, or reviewing .js/.mjs/.cjs files for correctness and best practices.

72

Quality

88%

Does it follow best practices?

Impact

No eval scenarios have been run

SecuritybySnyk

Passed

No known issues

SKILL.md
Quality
Evals
Security

Quality

Content

77%

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

This is a solid skill with strong actionability and workflow clarity, featuring executable code examples and explicit validation feedback loops. Its main weaknesses are moderate verbosity in explaining patterns Claude already knows (var vs const, optional chaining basics) and missing bundle files that the reference table depends on, which weakens the progressive disclosure structure.

Suggestions

Remove or significantly trim the 'Avoid var / Prefer const' and 'Optional Chaining' examples, as these are basic JS knowledge Claude already has — focus examples on less obvious patterns.

Provide the referenced bundle files (references/modern-syntax.md, etc.) or remove the reference table if they don't exist, as broken references reduce trust in the skill's structure.

Trim the MUST DO / MUST NOT DO constraints to only non-obvious project-specific rules rather than general JavaScript best practices Claude already follows.

DimensionReasoningScore

Conciseness

The skill is reasonably efficient but includes some unnecessary content. The constraints section lists things Claude already knows (e.g., 'Use `const` or `let`', 'Use optional chaining'), and the 'Avoid var / Prefer const' example is trivially obvious. The ✅/❌ pattern examples, while clear, cover basic knowledge Claude already possesses.

2 / 3

Actionability

The skill provides fully executable code examples with correct/incorrect patterns, specific tool commands (eslint --fix, --inspect), concrete coverage targets (85%+), and clear output templates. The code snippets are copy-paste ready and cover real-world patterns.

3 / 3

Workflow Clarity

The core workflow has clear sequencing with explicit validation checkpoints and feedback loops: 'if linter fails, fix all reported issues and re-run before proceeding', 'if leaks are found, resolve them before continuing', 'if coverage falls short, add missing cases and re-run.' This covers destructive/batch operation validation well.

3 / 3

Progressive Disclosure

The reference table with 'Load When' guidance is well-structured and clearly signaled. However, no bundle files were provided, meaning all five referenced files (references/modern-syntax.md, etc.) are missing, which undermines the progressive disclosure structure. The inline content also includes material that could be offloaded to those reference files.

2 / 3

Total

10

/

12

Passed

Description

100%

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 is a strong skill description that excels across all dimensions. It provides specific concrete actions, comprehensive trigger terms that developers would naturally use, explicit 'Use when' guidance with multiple scenarios, and clear scoping to vanilla JavaScript that distinguishes it from framework-specific or TypeScript skills.

DimensionReasoningScore

Specificity

Lists multiple specific concrete actions ('writes, debugs, and refactors JavaScript code') and names specific technologies and features (ES2023+, async/await, ESM modules, Node.js APIs, Web Workers, Fetch API, Promise-based async flows).

3 / 3

Completeness

Clearly answers both 'what' (writes, debugs, refactors JavaScript with modern features) and 'when' with an explicit 'Use when...' clause listing five specific trigger scenarios including building vanilla JS apps, async flows, performance optimization, Web Workers/Fetch, and file review.

3 / 3

Trigger Term Quality

Excellent coverage of natural terms users would say: 'JavaScript', 'async/await', 'Node.js', 'Web Workers', 'Fetch API', '.js/.mjs/.cjs', 'debug', 'refactor', 'performance', 'Promise'. These are terms developers naturally use when seeking JavaScript help.

3 / 3

Distinctiveness Conflict Risk

Clearly scoped to vanilla JavaScript with specific markers like 'ES2023+', 'ESM module systems', '.js/.mjs/.cjs' file extensions, and 'vanilla JavaScript applications' that distinguish it from TypeScript, React, or other framework-specific skills.

3 / 3

Total

12

/

12

Passed

Validation

100%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation11 / 11 Passed

Validation for skill structure

No warnings or errors.

Repository
Jeffallan/claude-skills
Reviewed

Table of Contents

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