tessl-labs/nestjs-best-practices
NestJS patterns -- modules, DI, exception filters, validation pipes, guards, interceptors, testing, config
98
89%
Does it follow best practices?
Impact
100%
1.36xAverage score across 12 eval scenarios
Passed
No known issues
Quality
Discovery
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 an excellent skill description that follows best practices. It provides comprehensive coverage of NestJS-specific capabilities, uses third person voice, includes an explicit 'Use when...' clause with multiple trigger scenarios, and is clearly distinguishable from other backend framework skills.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete NestJS concepts: modules, controllers, services, dependency injection, exception filters, validation pipes, guards, interceptors, custom providers, testing, and configuration. These are all concrete, actionable architectural patterns. | 3 / 3 |
Completeness | Clearly answers both what (NestJS patterns with comprehensive list of concepts) AND when (explicit 'Use when...' clause covering building/reviewing APIs, setting up projects, and migrating from Express). | 3 / 3 |
Trigger Term Quality | Includes natural keywords users would say: 'NestJS', 'APIs', 'NestJS project', 'Express to NestJS', plus specific technical terms like 'dependency injection', 'guards', 'interceptors' that developers would naturally mention when seeking help. | 3 / 3 |
Distinctiveness Conflict Risk | Highly distinctive with clear NestJS-specific terminology. The combination of 'NestJS', framework-specific concepts like 'guards' and 'interceptors', and the Express migration trigger creates a clear niche unlikely to conflict with generic Node.js or other framework skills. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
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 strong, actionable NestJS skill with excellent code examples and clear WRONG/RIGHT patterns that make correct usage unambiguous. The comprehensive checklist and verifier references add practical value. Main weaknesses are the monolithic length (could benefit from splitting advanced topics into separate files) and some verbosity in explanations that Claude likely doesn't need.
Suggestions
Extract advanced topics (custom providers, circular dependencies, guards/interceptors/middleware) into separate reference files and link from a shorter main SKILL.md
Remove explanatory text that describes what options do (e.g., 'whitelist: true -- strips properties not in the DTO') and trust Claude to understand from the code context
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The content is mostly efficient with good code examples, but includes some redundant explanations (e.g., explaining what whitelist does, repeating 'Key rules' sections). The WRONG/RIGHT pattern is useful but adds verbosity. Some sections like the execution order diagram and 'when to use which' explanations could be tighter. | 2 / 3 |
Actionability | Excellent actionability with fully executable, copy-paste ready code examples throughout. Every pattern shows concrete TypeScript code with proper imports, decorators, and complete implementations. The WRONG/RIGHT comparisons make correct usage crystal clear. | 3 / 3 |
Workflow Clarity | Clear structure with numbered sections, explicit execution order diagram for request lifecycle, and a comprehensive checklist at the end. The skill covers setup (main.ts bootstrap), implementation patterns, and testing in logical sequence. Validation steps are implicit in the testing section. | 3 / 3 |
Progressive Disclosure | The skill references verifiers at the end with clear links, but the main content is a monolithic 400+ line document. Some sections (like custom providers, circular dependencies) could be split into separate reference files. The structure is good with clear headings, but lacks the 'quick start → advanced references' pattern. | 2 / 3 |
Total | 10 / 12 Passed |
Validation
81%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 9 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
skill_md_line_count | SKILL.md is long (535 lines); consider splitting into references/ and linking | Warning |
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
Total | 9 / 11 Passed | |
Reviewed
Table of Contents