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.
62
44%
Does it follow best practices?
Impact
94%
1.13xAverage score across 3 eval scenarios
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./tests/ext_conformance/artifacts/agents-wshobson/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 use when seeking API design help. The specificity of capabilities could be significantly improved.
Suggestions
Replace vague aspirational language ('intuitive, scalable, maintainable APIs that delight developers') with concrete actions like 'define resource naming, design pagination, structure error responses, plan versioning strategies'.
Add more natural trigger terms users would say, such as 'endpoints', 'OpenAPI', 'Swagger', 'schema', 'HTTP methods', 'versioning', 'rate limiting', or 'API documentation'.
| 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', 'versioning', 'pagination', or 'HTTP methods'. | 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
22%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill reads more like a comprehensive tutorial or textbook chapter than a concise skill file 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 an API. The code examples are illustrative but not fully executable, and the massive inline content should be split into referenced files.
Suggestions
Remove the 'Core Concepts' section entirely — Claude already knows what REST resources, HTTP methods, and GraphQL schemas are. Focus only on project-specific conventions and non-obvious patterns.
Add a clear sequential workflow: e.g., '1. Choose paradigm (REST vs GraphQL) based on [criteria] → 2. Define resource model → 3. Design endpoints/schema → 4. Validate against checklist → 5. Generate OpenAPI spec'
Move the detailed code patterns (pagination, DataLoader, resolver design) into the referenced files (references/rest-best-practices.md, references/graphql-schema-design.md) and keep only a brief summary with links in SKILL.md
Make code examples self-contained and executable, or explicitly note they are templates requiring project-specific implementations of helper functions
| 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 'Core Concepts' section is almost entirely redundant knowledge. Lists like 'GET: Retrieve resources (idempotent, safe)' and 'Resources are nouns, not verbs' are textbook material Claude doesn't need. | 1 / 3 |
Actionability | Contains concrete Python/GraphQL code examples that are mostly executable (FastAPI endpoints, Ariadne resolvers, DataLoader patterns). However, many examples depend on undefined helper functions (build_query, fetch_users, count_users, etc.), making them not truly copy-paste ready. The code is more illustrative than executable. | 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 guiding Claude through a design process. No validation checkpoints, no decision points for choosing between REST and GraphQL, no step-by-step design workflow. | 1 / 3 |
Progressive Disclosure | References to external files are listed at the end (references/, assets/, scripts/), which is good structure. However, the main file is a monolithic wall of content that should have been split — the detailed GraphQL schema, resolver patterns, and DataLoader implementations would be better as referenced files, keeping the SKILL.md as a concise overview. | 2 / 3 |
Total | 6 / 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 (529 lines); consider splitting into references/ and linking | Warning |
Total | 10 / 11 Passed | |
- Repository
- Dicklesworthstone/pi_agent_rust
- Commit
47823e3
- Reviewed
Table of Contents
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