Expert TypeScript developer specializing in type-safe application development, advanced type systems, strict mode configuration, and modern TypeScript patterns. Use when building type-safe applications, refactoring JavaScript to TypeScript, or implementing complex type definitions.
66
61%
Does it follow best practices?
Impact
Pending
No eval scenarios have been run
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./skills/typescript-expert/SKILL.mdQuality
Discovery
67%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 structure with explicit 'Use when' guidance, making it complete. However, it relies on somewhat abstract category terms rather than concrete actions, and the trigger terms could be expanded to include more natural variations users might say. The TypeScript focus provides reasonable distinctiveness but could be sharper.
Suggestions
Replace abstract categories with concrete actions: 'Configure strict tsconfig settings, create generic types and utility types, migrate JavaScript codebases to TypeScript, resolve type errors'
Expand trigger terms to include common variations: 'TS', '.ts files', 'tsconfig', 'generics', 'interfaces', 'type errors', 'strict null checks'
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Names the domain (TypeScript) and mentions some areas like 'type-safe application development, advanced type systems, strict mode configuration, and modern TypeScript patterns' but these are more categories than concrete actions. Lacks specific verbs like 'configure tsconfig', 'create generic types', or 'migrate codebases'. | 2 / 3 |
Completeness | Clearly answers both what ('Expert TypeScript developer specializing in type-safe application development, advanced type systems, strict mode configuration, and modern TypeScript patterns') and when ('Use when building type-safe applications, refactoring JavaScript to TypeScript, or implementing complex type definitions') with explicit trigger guidance. | 3 / 3 |
Trigger Term Quality | Includes 'TypeScript', 'type-safe', 'JavaScript to TypeScript', and 'type definitions' which are relevant keywords. However, missing common variations users might say like 'TS', 'types', 'generics', 'interfaces', '.ts files', 'tsconfig', or 'strict null checks'. | 2 / 3 |
Distinctiveness Conflict Risk | TypeScript focus provides some distinction, but 'application development' and 'modern patterns' are generic enough to potentially overlap with general JavaScript or web development skills. Could conflict with broader coding assistance skills. | 2 / 3 |
Total | 9 / 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 guidance with executable code examples and a clear TDD workflow, but suffers severely from verbosity and poor organization. It explains many concepts Claude already knows (utility types, strict mode basics) and repeats key advice multiple times. The content would benefit greatly from being split into multiple files with SKILL.md serving as a concise overview.
Suggestions
Reduce content by 70%+ by removing explanations of concepts Claude knows (what Partial/Pick/Omit do, what strict mode is, basic TypeScript features) and keeping only project-specific patterns or non-obvious guidance
Split into multiple files: SKILL.md (overview + quick reference), PATTERNS.md (detailed patterns), TESTING.md (test examples), SECURITY.md (security considerations)
Consolidate repeated advice (avoid 'any' appears in sections 2, 4, 8, 13) into a single 'Critical Rules' section
Remove the OWASP table entirely - it adds little actionable value and Claude can reference OWASP directly if needed
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | Extremely verbose at ~600+ lines with significant redundancy. Explains concepts Claude already knows (what strict mode is, what utility types do, basic TypeScript features). Multiple sections repeat the same advice (avoid 'any' appears 5+ times). The OWASP table and extensive pattern explanations add bulk without proportional value. | 1 / 3 |
Actionability | Provides fully executable, copy-paste ready code examples throughout. Every pattern includes concrete TypeScript code with clear good/bad comparisons. Test examples are complete with imports and assertions. Commands for verification are specific (npx tsc --noEmit, npx vitest run --coverage). | 3 / 3 |
Workflow Clarity | Clear TDD workflow with explicit steps (Write Failing Test → Implement → Refactor → Verify). Step 4 includes specific validation commands. Pre-implementation checklist provides explicit checkpoints across three phases. The workflow is well-sequenced with clear verification gates. | 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.md. Content that should be in separate files (patterns, security, testing) is all embedded. No navigation structure or links to detailed materials. | 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 (829 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 | |
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