api-design-principles
Master REST and GraphQL API design principles to build intuitive, scalable, and maintainable APIs that delight developers. Use when designing new APIs, reviewing API specifications, or establishing API design standards.
72
41%
Does it follow best practices?
Impact
93%
1.13xAverage score across 6 eval scenarios
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./plugins/backend-development/skills/api-design-principles/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.
The description has a solid structure with an explicit 'Use when...' clause that covers key scenarios, earning good marks for completeness. However, it relies on aspirational buzzwords ('delight developers', 'intuitive, scalable, and maintainable') instead of listing concrete actions, and it misses many natural trigger terms users would employ when seeking API design help. The specificity of capabilities could be significantly improved by enumerating concrete design tasks.
Suggestions
Replace vague aspirational language ('intuitive, scalable, and maintainable APIs that delight developers') with concrete actions like 'define resource naming, design pagination, structure error responses, plan versioning strategies, create OpenAPI/GraphQL schemas'.
Add more natural trigger terms users would say, such as 'endpoints', 'OpenAPI', 'Swagger', 'API versioning', 'schema design', 'request/response format', 'API documentation', '.yaml spec'.
Improve distinctiveness by specifying what makes this skill different from general backend development or coding skills—e.g., focus on design patterns, conventions, and specification review rather than implementation.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Names the domain (REST and GraphQL API design) and mentions some actions ('designing new APIs, reviewing API specifications, establishing API design standards'), but the core description uses vague aspirational language ('intuitive, scalable, and maintainable APIs that delight developers') rather than listing concrete specific actions like 'define resource naming conventions, design pagination schemes, structure error responses'. | 2 / 3 |
Completeness | Clearly answers both 'what' (REST and GraphQL API design principles) and 'when' with an explicit 'Use when...' clause covering three trigger scenarios: designing new APIs, reviewing API specifications, or establishing API design standards. | 3 / 3 |
Trigger Term Quality | Includes some relevant keywords like 'REST', 'GraphQL', 'API design', 'API specifications', and 'API design standards', but misses common natural variations users might say such as 'endpoints', 'routes', 'OpenAPI', 'Swagger', 'schema design', 'API versioning', 'request/response format', or 'API documentation'. | 2 / 3 |
Distinctiveness Conflict Risk | The focus on API design principles for REST and GraphQL provides some distinctiveness, but 'designing new APIs' and 'reviewing API specifications' could overlap with general coding skills, backend development skills, or documentation skills. The phrase 'delight developers' is fluffy and doesn't help differentiation. | 2 / 3 |
Total | 9 / 12 Passed |
Implementation
14%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill reads like a tutorial or reference guide rather than an actionable skill for Claude. It spends significant tokens explaining concepts Claude already knows (HTTP methods, REST principles, GraphQL basics) while lacking a clear workflow for actually designing APIs. The content would benefit enormously from being condensed to decision-relevant guidance and split across referenced files.
Suggestions
Remove all explanations of basic concepts Claude already knows (HTTP method semantics, what REST/GraphQL are, what pagination is) and focus only on project-specific conventions or non-obvious design decisions.
Add a clear step-by-step workflow for API design (e.g., 1. Define resources → 2. Design endpoints → 3. Define error format → 4. Review against checklist) with validation checkpoints.
Split detailed code patterns (GraphQL schema, DataLoader, pagination) into separate referenced files, keeping SKILL.md as a concise overview with navigation links.
Make code examples self-contained and executable rather than relying on undefined helper functions like build_query(), fetch_users(), etc.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | Extremely verbose at ~400+ lines. Explains basic concepts Claude already knows (what HTTP methods mean, what REST resources are, what GraphQL queries/mutations/subscriptions are). The 'When to Use This Skill' section, 'Core Concepts' explaining REST and GraphQL fundamentals, and bullet-point best practices are all padding that adds no novel knowledge for Claude. | 1 / 3 |
Actionability | Contains concrete Python/GraphQL code examples that are mostly executable (FastAPI endpoints, Ariadne resolvers, DataLoader patterns), but many rely on undefined helper functions (build_query, fetch_users, count_users, etc.) making them not truly copy-paste ready. The code serves more as illustrative patterns than executable guidance. | 2 / 3 |
Workflow Clarity | There is no clear workflow or sequenced process for designing an API. The content is a reference dump of patterns and best practices without any step-by-step process, decision points, or validation checkpoints. For a skill about 'API design,' there should be a clear workflow for how to approach designing an API from scratch. | 1 / 3 |
Progressive Disclosure | Monolithic wall of text with no references to external files. All content—REST patterns, GraphQL patterns, best practices, pitfalls—is inlined in a single massive document. Content like the GraphQL schema examples, DataLoader patterns, and detailed code could easily be split into referenced files. | 1 / 3 |
Total | 5 / 12 Passed |
Validation
90%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 10 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
skill_md_line_count | SKILL.md is long (519 lines); consider splitting into references/ and linking | Warning |
Total | 10 / 11 Passed | |
- Repository
- wshobson/agents
- Commit
27a7ed9
- Reviewed
Table of Contents
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